The officer warned me . . . . . . . . the office until five o’clock.

The correct answer is D. not to leave.

The officer warned me not to leave the office until five o’clock. This means that the officer told me that I should not leave the office until five o’clock. The officer may have warned me not to leave because there was a dangerous situation outside, or because the officer needed me to stay in the office to help with something.

The other options are incorrect because they do not accurately reflect the meaning of the sentence. Option A, don’t leave, is incorrect because it does not include the negative particle “not.” Option B, to leave, is incorrect because it does not indicate that the officer was telling me not to leave. Option C, to not leave, is incorrect because it is redundant.