A. It is known that Julius Caesar had kidnapped by pirates on the way across the Aegean Sea.
B. It is known that Julius Caesar was kidnapped by pirates on the way across the Aegean Sea.
Feedback The Passive Voice is formed according to this rule: Subject - Be+ Past Participle - Preposition 'BY' - Agent (who or what carries out the action). The right form for Past Simple Passive is: was/were + past participle or verb+ -ed. Other answers are incorrect or illogical.
C. It is known that Julius Caesar was kidnapping by pirates on the way across the Aegean Sea.
D. It is known that Julius Caesar kidnapped pirates on the way across the Aegean Sea.