60. Tetanus refers to
(A) the partial sustained contraction of major supporting muscles.
(B) the all-or-none contraction of a single muscle fiber.
(C) a stronger contraction resulting from the activation of multiple motor units.
(D) a smooth and sustained contraction, resulting from wave summation.
(E) a state of muscle fatigue caused by the depletion of ATP and the accumulation of lactate.