The guest room key grants access to a specific guest room, usually issued at check-in.
- An emergency key is for staff use during emergencies and does not unlock individual guest rooms.
- A master key allows hotel management or staff to access all rooms, but is not provided to guests.
- A card key is an electronic alternative to a traditional key for opening guest room locks; its applicability varies by hotel type.
Therefore, the accurate answer is Guest room key.