Which of the Following Is NOT True of Muscle Fatigue

Which of the following is NOT true of muscle fatigue?

A) It involves a decrease in the force of muscle contraction, even when the muscle is still under stimulation.
B) It may be caused by conduction failure, due to accumulation of K⁺ ions in the transverse tubules of skeletal muscle fibers
C) It usually occurs when a muscle is being stimulated during very light work or exercise.
D) It may be caused by decreased responsiveness of a muscle fiber to low pH, resulting from a build-up of lactic acid
E) All of these are true of muscle fatigue.