Decreased Muscle Tone or Spasm in Response to Heat Is

Decreased muscle tone or spasm in response to heat is primarily caused by

A) Increased rate of firing of type II efferents, resulting in relaxation response
B) Decreased rate of firing of type Ib efferents, resulting in decreased production of neurotransmitters at the neuromuscular junction
C) Increased golgi tendon organ (GTO) activity, resulting in decreased stretch on muscle spindle
D) Decreased gamma efferent activity, resulting in decreased muscle spindle activity