Correct option is C
Option (c) is the correct passive voice of the given sentence.
· In passive voice, the object of the active sentence (in this case, "my tickets") becomes the subject of the passive sentence.
· The active sentence "Who stole my tickets?" is in the simple past tense, so the passive form must also be in the simple past tense.
· The structure of a passive sentence in the simple past tense is typically "was/were + past participle of the verb." Here, "stolen" is the past participle of "steal."
· Therefore, option (c) "By whom were my tickets stolen?" is the correct transformation into passive voice, maintaining the formal structure and proper use of "whom."