Answer:
My diary isn't in its regular place; someone must have taken it.
Explanation:
The correct answer to this sentence is must have taken, due to that the sentence is being used in past tense. Even though some of the other options use the word "taken" they would not make sense with this sentence, as it would be improper. So once again, the correct option is must have taken.
Hope this helps! Have an amazing day! :)
