The given sentence is in an active voice form, hence we need to convert it into a passive voice form.
We need to follow these instructions while changing the voice of an assertive sentence.
Find the subject (We) and object (good news) of the sentence and exchange their places.
The given sentence is in the present indefinite tense.
The passive verb form for the present indefinite sentence: is/are + V3 + by + subject.
So, 'expect' changes into 'is expected'.
At last line up the remaining part.
Following this structure, we get the 4th option as the correct answer.  
Following these steps, we finally get- Good news is expected by us about the corona vaccine.

In Active Voice, a sentence emphasizes the subject, performing an action.
In Passive Voice, a sentence emphasizes the action or the object of the sentence.
The given sentence is in the active voice and 'our advocate' is the subject and 'the case' is the object.
When we convert this sentence into passive voice, the subject 'our advocate' of the active voice becomes the object, the object 'the case' becomes the subject.
The passive format "is + being + V3 (argued)" should be used.
This is the active and passive voice rule for the present continuous tense.

An imperative sentence does not normally have a subject. It is used to express a command or request.
 The imperative sentence in the active and passive voice takes the following form:
V1 + Object.
Let + object + be + past participle.
Example:  Help him. (Active Voice) Let him be helped. (Passive Voice)
Following the active voice form, we finally get- Send this email immediately.

In Active Voice, a sentence emphasizes the subject, performing an action.
In Passive Voice, a sentence emphasizes the action or the object of the sentence.
The given sentence is in the passive voice and 'The light' is the subject and 'her' is the object.
When we convert this sentence into active voice, the subject 'The light' of the passive voice becomes the object, the object 'her' becomes the subject 'she'.
The passive format "was + V3 (switched)" should be changed into the active format "switched".
This is the active and passive voice rule for the past simple tense.

In Active Voice, a sentence emphasizes the subject, performing an action.
In Passive Voice, a sentence emphasizes the action or the object of the sentence.
The given sentence is in the passive voice and 'The ticket' is the subject and 'the airlines' is the object.
When we convert this sentence into active voice, the subject 'The ticket' of the passive voice becomes the object, the object 'the airlines' becomes the subject.
The passive format "will + be + V3 (sent)" should be changed into the active format "will + V1 (send)".
This is the active and passive voice rule for the future simple tense.

The given sentence is in The Passive Voice.
As per the question we have to change it into Active Voice.
The process of transformation as follows: 'One' will be added.
Because the given sentence has no subject it is a general statement that is why true everywhere.
Therefore, 'one' is used as a subject.
'Cannot be achieved' will be changed into 'cannot achieve' in the active voice.
The rest of the sentence will be written as it is.

If a verb requires an object after it, it is a transitive verb.
If a verb doesn't require an object after it, it is an intransitive verb.
For example:
The girls carry water to their village. (transitive verb) A light was shining. (intransitive verb)
There are certain verbs that are used in a particular pattern given below:
Subject + verb + noun/pronoun + present participle(-ing form).
Some of the verbs are given below:
Hate/love, stop/start, finish, enjoy, prefer, keep, rest, worth, propose, regret, etc.
Example: She hates going out in the night.
According to the rule and the example given above, 'has started bringing' will be used instead of 'has started bring' in the 2nd part of the sentence.

Detailed Solution
The correct answer is- The ending of the play surprised the audience.
Additional Information
The given sentence is in a passive voice form, hence we need to convert it into an active voice form.
Find the subject (The audience) and object (the ending of the play) of the sentence and exchange their places.
The given sentence is in the simple past tense.
The active verb form for simple past is: Subject + past participle form of the verb + Object.
So, 'was surprised' changes to 'surprised'. At last line up the remaining part.
Following these steps, we finally get- The ending of the play surprised the audience.