When a physician elicits the knee-jerk reflex by tapping deep tendons in the knee, the normal response is for the lower leg to swing forward. When this happens:

Muscles in the back of the lower leg are contracting but that in the front are relaxing.

Muscles in the front of the lower leg are contracting but that in the back are relaxing.

Muscles in the back of the thigh are contracting but that in the front are relaxing.

Muscles in the front of the thigh are contracting but that in the back are relaxing.

When a physician elicits the knee-jerk reflex by tapping deep tendons

1.	When a physician elicits the knee-jerk reflex by tapping deep tendons in the knee, the normal response is for the lower leg to swing forward. When this happens:
A.	Muscles in the back of the lower leg are contracting but that in the front are relaxing.
B.	Muscles in the front of the lower leg are contracting but that in the back are relaxing.
C.	Muscles in the back of the thigh are contracting but that in the front are relaxing.
D.	Muscles in the front of the thigh are contracting but that in the back are relaxing.
Answer» E.