Topic: Voice,

Best Answer Explained in Below-:

The sentence "I saw him go to the garden" expresses an observation made by the speaker regarding someone else's action. To convey this idea in a passive construction, the correct choice must accurately reflect the original meaning while maintaining proper grammatical structure.

Option B, "He was seen to go to the garden," effectively captures this meaning. It indicates that an observation was made about him going to the garden, preserving the action and introducing the subject in a passive manner. The phrase "was seen to go" correctly uses the infinitive "to go," which implies the act of going happened as part of the observation.

In contrast, Option A, "He was seen go to the garden," is grammatically incorrect; the verb form "go" should be paired with "to" as an infinitive. Option C, "He was been seen to go to the garden," contains another error with the incorrect use of "been," which is unnecessary and incorrect in this context. Option D, "He went to the garden was seen," also misrepresents the meaning and fails to adhere to standard grammatical rules.

Thus, Option B is not only the grammatically correct choice, but it also most faithfully conveys the action observed by the speaker.