Select the option that expresses the given sentence in passive voice.
They propose to build a dam for irrigation purposes.

Correct option is D

The correct passive voice of the given sentence is (d).
Definitions:
· Active Voice: Subject performs the action.
· Passive Voice: Action is performed upon the subject.
Rules of Conversion from Active to Passive (for Infinitive constructions like “to build”):
· The structure is maintained using an impersonal construction:
· Active: They propose to + V1
· Passive: It is proposed to + V1 (unchanged)
Structure:
· Active Voice: Subject + propose + to + V1 + object
· Passive Voice: It + is proposed + to + V1 + object
Example:
· Active: They plan to start the project next week.
· Passive: It is planned to start the project next week.
Other options are incorrect because:
· (a) Imperative mood; not passive.
· (b) “Has been built” is past perfect tense, not correct contextually.
· (c) Incomplete and grammatically faulty.