Which sentence contains a modal-perfect form error in past deduction or criticism?
The visitor must have entered the boathouse.
The caretaker must had locked the west gate before the delivery arrived.✓Bonne réponse
The courier can't have driven to the cabin.
We should have tested the microphone.
Explication
The sentence about the caretaker is erroneous because must had locked is not a modal-perfect construction. A past deduction requires must have followed by the participle locked.