The correct option is D had been kidnapped
Here, 'had been kidnapped' in Past Perfect continuous Tense is correct because it
is used to indicate an action that started at some point in the past and may or
may not be complete.
'Has kidnapped' in present perfect is
incorrect because it is used to indicate an action which started in the past
and has continued up untill now.
'Was kidnapped' in past simple is incorrect because
it indicates an action that has already been completed.
'Was kidnapping' is grammatically incorrect.