Which of the following statements is incorrect?

Options

A. Calmodulin and calsequestrin are calcium binding proteins found in smooth muscles and skeletal muscles respectively
B. Length of a muscle fibre shortens during isometric contraction while it remains same during isotonic contraction
C. Summation occurs when a second stimulus is given before complete relaxation of muscle in response to the first stimulus
D. Muscle fatigue and cramps are caused due to accumulation of lactic acid in them

Answer

B