Given What You Know About the Musculature of the Respiratory

Given what you know about the musculature of the respiratory system, what is the most likely explanation for why you can change your breathing rate at any time?

A) the smooth muscles of the respiratory tract can be consciously controlled, unlike like other involuntary systems in the body
B) breathing rate is achieved through skeletal muscles, which are under partial voluntary control
C) in addition to smooth muscles that allow for conscious control, there are likely skeletal muscles involved that can be consciously controlled
D) there are skeletal muscles involved in breathing that display smooth muscle-like autorhythmicity