One's promises are kept.
Ones promises must kept.
Ones promises were kept.
One's promises must be kept.
Answer is Wrong!
Answer is Right!
The correct answer is D. One’s promises must be kept.
A. One’s promises are kept is in the passive voice, which is not the correct way to express this sentence. The active voice is more direct and concise.
B. Ones promises must kept is grammatically incorrect. The correct spelling is “One’s promises must be kept.”
C. Ones promises were kept is in the past tense, which is not the correct tense for this sentence. The sentence is about a general rule, not a specific event.
D. One’s promises must be kept is in the correct tense and voice. It is also the most concise and direct way to express this sentence.