Correct option is A
The correct passive voice is
“The proposal had been rejected by the committee.”
Conversion Rules (Past Perfect → Passive):
·
Active structure: Subject +
had + V³ + Object.
·
Passive structure: Object +
had been + V³ +
by + Subject.
· Applying:
Committee (S) + had + rejected (V³) +
proposal (O) →
Proposal (O) + had been + rejected (V³) + by +
committee (S).
·
Structure:
·
Active:
The committee
had rejected
the proposal.
·
Passive:
The proposal
had been rejected
by the committee.
·
Why others are wrong:
· (b)
was rejecting → progressive, wrong tense & form.
· (c)
was rejected → Simple Past, not Past Perfect.
· (d)
is rejected → Simple Present, wrong tense.