What is right patellar tendon

Which of the following occur in response to an increase in the length of the right knee extensors in response to a quick tap applied to the right patellar tendon?  An increase in the amount of

A. open force-gated channels in the peripheral terminals of IA muscle-spindle stretch receptor neurons whose peripheral terminals are in the right knee extensor muscle.

B. glutamate released from the axon terminals of knee extensor motor neurons whose axon terminals are located near the right knee extensor muscle.

C. sodium conductance in the dendrites of knee extensor motor neurons whose cell bodies are located in the left half of the spinal cord.