Which of the following options is the most suitable conversion of the following sentence into active voice?
Why aren't benign tumours rejected by the body?
Show answer & explanation
Correct answer: C
Explanation
The original sentence is in the Present Indefinite (Simple Present) tense in its negative interrogative form (aren't... rejected).
For a singular subject like "the body," the auxiliary verb for the negative present tense is "doesn't."
Active voice sentence: Why doesn’t the body reject benign tumours?
Therefore, option “C” is the correct answer.