Q:

They said, “It was raining heavily, when they came out of the theatre.

• 1
  They said that it was raining heavily, when they had come out of the theatre.
• 2
  They said that it had been raining heavily, when they came out of the theatre.
• 3
  They said that it rained when they had come out of the theatre
• 4
  They said that it had been raining heavily, when they had come out of the theatre.