Pitch of sound is determined by its
frequency
The explanation of the correct option
In the case of option A,
The explanation of the incorrect option
In the case of option B,
The maximum displacement or distance moved by a point on a vibrating body or wave from its equilibrium position is called amplitude.
In the case of option C,
Speed is defined as the distance traveled by a body in a certain amount of time.
In the case of option D,
Loudness is the quality of sound that determines the strength of the auditory sense produced.
Hence, option A is the correct option.