Identify the correct passive voice form of the following sentence:-

One should keep one's promises.

Promises should be kept.

The correct answer is Option (2) - Promises should be kept.

The correct passive voice form of the sentence "One should keep one's promises" is: Promises should be kept.

• Active voice: One should keep one's promises.

• Passive voice: The object (promises) becomes the subject → Promises should be kept.

Other options:

• Promises need to be kept-  it changes the modal verb “should” to “need to,” which is a change in meaning.

• Nobody keeps promises – completely unrelated in voice and meaning.

• One has kept one's promises – changes tense and meaning entirely.