The packet has not been opened by anyone.

The correct answer is B. No one has opened the packet.

A. Anyone has not opened the packet is grammatically incorrect. The negative should be placed before the subject, not after it.
C. No one has not opened the packet is also grammatically incorrect. The double negative makes the sentence meaningless.
D. No one has been opening the packet is also incorrect. The verb should be in the past participle form, not the present participle form.

The sentence “The packet has not been opened by anyone” means that no person has opened the packet. This can be expressed in other ways, such as “The packet is unopened,” “No one has touched the packet,” or “The packet is still sealed.”