From the given alternatives, choose the one which best expresses the sentence in Active/Passive voice.
She spoke to the manager on duty

The manager on duty was spoken to by her

The correct answer is The manager on duty was spoken to by her.

The original sentence is in active voice, with the subject "she" and the verb "spoke". To change it to passive voice, we make the object of the active sentence, "manager on duty", the subject of the passive sentence. The verb "spoke" becomes "was spoken to", and we add the preposition "by" to show who is doing the action. This gives us the passive voice sentence "The manager on duty was spoken to by her".

The other options are incorrect.

• The manager was spoken to by her on duty is also in passive voice, but it is not grammatically correct. The preposition "on" should not be used with the verb "spoken to".
• She was spoken to by the manager on duty is in active voice, but it changes the meaning of the sentence. The original sentence means that she spoke to the manager, but the passive voice sentence means that the manager spoke to her.
• She was the manager to be spoken to on duty is not in passive voice. It is a sentence fragment that does not have a subject or a verb.