Question

After he _____ the answer, the judge started to laugh. had been hearing was hearing had heard was heard

Answer 1

After he had heard the answer, the judge started to laugh

Answer 2

After he HAD HEARD the answer, the judge started to laugh.
Good luck

Answer 3

After he had heard the answer, the judge started to laugh.

The past perfect tense "had heard" is used in this sentence to indicate that the action of hearing the answer occurred before the judge started to laugh. The past perfect tense is used to express an action that happened before another past action or a specific point in the past. In this case, the action of hearing the answer (had heard) happened before the action of the judge starting to laugh.

Source: - English Grammar Practice: "George made no answer and we found that he had been asleep for some time. ... He knew the poem by heart when he had heard it several times."

I hope this helps! Let me know if you have any further questions.