Correct Answer: Sheath

Solution : The correct choice is the first option.

A sheath is a protective covering, typically made of leather or another material, in which the blade of a sword is kept when it is not in use.

The meanings of the other options are as follows:

• A pantry is a room or storage area where food, dishes, and linens are kept.
• A dyke is a long wall or embankment built to prevent flooding from the sea.
• An infirmary is a place, usually within a larger institution, for the care and treatment of the sick or injured.

Therefore, the correct answer is sheath.