Select the option that expresses the given sentence in passive voice.

One must adopt a life of self-control.

A life of self-control must be adopted by one.

The correct passive voice of the given sentence is A life of self-control must be adopted by one.

The active voice of the sentence is One must adopt a life of self-control. This sentence is in the simple present tense, which is used to describe an action that is happening now or that is happening repeatedly. The passive voice of the sentence is formed by putting the subject of the active sentence after the verb "to be" and the past participle of the main verb. In this case, the subject of the active sentence is "one" and the main verb is "adopt." The past participle of "adopt" is "adopted." So, the passive form of the sentence is A life of self-control must be adopted by one.

The other options are incorrect because:

• A life of self-control was adopted by one. is in the simple past tense, while the original sentence is in the simple present tense.
• A life of self-control will be adopted by one. is in the future tense, while the original sentence is not describing an action that will happen in the future.
• A life of self-control has adopted by one. is in the present perfect tense, while the original sentence is not describing an action that has already happened.
• A life of self-control adopted by one. lacks the verb "to be."