Answer : 3. "alternative"
Explanation :

The most appropriate option to fill in the blank is:

Official

Explanation: In this context, the word "official" suggests that the medicine being administered is recognized and approved by the relevant authorities or medical professionals. It implies that the medicine is legitimate and prescribed within the official protocols of medical practice.

The other options do not fit well in the context:

"Eminent" means distinguished or noteworthy, but it doesn't directly relate to medicine in this context.

"Alternative" suggests a different option, which may not align with the doctor's directive.

Insightful" refers to having a deep understanding or perception, which doesn't make sense in the context of administering medicine.