Read the sentence.

Tension erupted in the room when it was revealed that the villain knew that the spy withholding information.

Which is the best revision of the sentence?

Tension will erupt in the room when it was revealed that the villain knew that the spy withholding information.
Tension erupted in the room when it reveals that the villain knew that the spy withholding information.
Tension erupted in the room when it was revealed that the villain will know that the spy withholding information.
Tension erupted in the room when it was revealed that the villain knew that the spy withheld information.

Tension erupted in the room when it was revealed that the villain knew that the spy withheld information.

The best revision of the sentence is:

Tension erupted in the room when it was revealed that the villain knew that the spy withheld information.

The best revision of the sentence is:

"Tension erupted in the room when it was revealed that the villain knew that the spy withheld information."

To determine the best revision, we need to focus on verb tenses and subject-verb agreement. In the original sentence, the verb "erupted" is in the past tense, indicating that the tension has already happened. Therefore, we need to keep the verb tense consistent throughout the sentence.

This eliminates options 1 and 3 since they use the future tense "will erupt," which does not match the past tense usage in the rest of the sentence.

Option 2, "Tension erupted in the room when it reveals that the villain knew that the spy withholding information," contains a subject-verb agreement error. The subject "it" does not agree with the verb "reveals," which should be in the past tense to match the verb "erupted."

Therefore, the correct choice is option 4: "Tension erupted in the room when it was revealed that the villain knew that the spy withheld information." It maintains the past tense verb "erupted" and uses the correct past tense verb "withheld" to match the spy's action.