The Tension Produced During Skeletal Muscle Contraction Can Be Increased

The tension produced during skeletal muscle contraction can be increased by all of the following EXCEPT

A) recruiting motor units.
B) initiating the contraction when the muscle is at its optimum length.
C) increasing the load on the muscle.
D) increasing the frequency of action potentials in the motor neuron innervating the muscle.
E) increasing the frequency of action potentials in the muscle fiber.