I . . . . . . . . lie from now on. A. don’t B. didn’t C. haven’t D. won’t

The correct answer is D. won’t.

The other options are incorrect because they do not express a future intention.

• Option A, don’t, expresses a present fact.
• Option B, didn’t, expresses a past fact.
• Option C, haven’t, expresses a present negative fact.

The sentence “I won’t lie from now on” expresses a future intention. The speaker is saying that they will not lie in the future.