Question

which part of the inner ear houses receptors most responsive to rotational (angular) movements of the head?

Explanation:

The inner ear's semicircular canals (labeled A in the diagram) contain receptors (cristae ampullaris) that detect rotational (angular) head movements. The cochlea (D) is for hearing, and other labeled parts like B/C are related to linear acceleration or other functions, but A (semicircular canals) is specific to angular motion.

Answer:

A (the semicircular canals, labeled as A in the diagram)