The correct answer is: B. They said that it had been raining heavily, when they came out of the theatre.
The sentence “They said, ‘It was raining heavily, when they came out of the theatre.'” is in the past tense. This means that the action of raining was happening at a time in the past that is before the time of speaking. The past perfect tense is used to talk about an action that was happening before another action in the past. In this case, the action of raining was happening before the action of coming out of the theatre. Therefore, the correct answer is B.
The other options are incorrect because they do not use the past perfect tense. Option A uses the simple past tense, which is used to talk about an action that happened at a specific time in the past. Option C uses the simple present tense, which is used to talk about an action that happens regularly or repeatedly. Option D uses the past participle “rained,” which is used to form the past tense and past participle of the verb “to rain.”
Here is a diagram that shows the time order of the events:
- Before: It was raining heavily.
- At the same time: They came out of the theatre.
I hope this explanation is helpful! Let me know if you have any other questions.