Correct Answer: Acoustics

Solution : The first option is the correct choice.

Acoustics is a branch of physics concerned with the properties of sound. It specifically deals with the study of sound, its production, transmission, and effects.

The meanings of the other options are as follows:

• An anchor is a heavy object attached to a rope or chain and used to moor a ship to the sea bottom.
• An anarchist is a person who believes in or promotes anarchy, i.e., the absence of government or authority.
• Apiary is a place where bees are kept, especially a collection of beehives.

Therefore, the correct answer is acoustics.