An object emits a frequency of 150Hz when stationary. What can be said about the pitch of the sound being emanated as the object is approaching you? What can be said about the pitch of a sound being emanated as the object is moving away from you?

A. The pitch increases as it approaches; the pitch decreases as it moves away.
B. The pitch decreases as it approaches; the pitch increases as it moves away.
C. The pitch remains constant regardless of motion.
D. The pitch is unpredictable based on motion.