The Speed of Sound in Biological Tissue Is 1500 M/s $\times$

Multiple Choice

The speed of sound in biological tissue is 1500 m/s. To resolve features with sizes of the order of two millimeters, the frequency of the sound wave used by a doctor is

A) larger than 3.0 $\times$ 10⁵ Hz.
B) smaller than 3.0 $\times$ 10⁵ Hz.
C) 7.5 $\times$ 10⁵ Hz.
D) larger than 7.5 $\times$ 10⁵ Hz.
E) smaller than 7.5 $\times$ 10⁵ Hz.