Normal Aging Results in Progressive Loss of Muscle Mass Characterized

Normal aging results in progressive loss of muscle mass characterized by:

A) Death of alpha motorneurons at the spinal cord resulting in decline of innervation to individual muscles.
B) Reduction in size but not number of muscle fibers.
C) Atrophy of type I fibers and hypertrophy of Type II muscle fibers.
D) Loss of muscle mass beginning in the sixth decade of life.