The old man could not remember where he . . . . . . . his money.

The correct answer is D. had deposited.

The old man is talking about something that happened in the past, so the verb must be in the past tense. The other options are not in the past tense.

• A. deposits is in the present tense.
• B. is depositing is in the present progressive tense.
• C. will deposit is in the future tense.

The old man is not talking about something that is happening now or will happen in the future. He is talking about something that happened in the past. Therefore, the correct verb tense is the past tense.