The courier . . . . . . . . three days ago, but why haven’t you received it yet? A. has been sent B. has sent C. was sent D. sent

The correct answer is: A. has been sent

The courier is the one who sends the package, so the sentence should be in the passive voice. The past participle “sent” is used to form the passive voice. The other options are not in the passive voice.

• B. has sent is in the active voice. The subject of the sentence is “the courier,” and the verb is “has sent.” This sentence means that the courier sent the package.
• C. was sent is also in the passive voice. However, the past participle “sent” is used with the auxiliary verb “was.” This sentence means that the package was sent.
• D. sent is in the simple past tense. This sentence means that the courier sent the package at a specific time in the past.

In this case, we don’t know when the courier sent the package, so the passive voice is the best option.