Select all that apply. For the evidence stated in each sentence, which sentences use present deduction correctly?
The smoke sensor is powered off, so it must to be detecting smoke in the empty corridor.
The island ferry is documented in dry dock all day, so that vessel can't be the island ferry.✓Correct answer
The serial number belongs to another model, so this mustn't be the ordered projector.
The display reads signal locked and the antenna is following the satellite, so it must be tracking the signal.✓Correct answer
Explanation
The ferry's documented dry-dock location rules out the vessel identification with can't be, and the locked signal plus following antenna supports must be tracking. Must to be is malformed, while mustn't be misuses prohibition language for a negative inference about the projector.