Answer:
B. muscle relaxation
Step-by-step explanation:
Sarcoplasmic reticulum store intracellular calcium in skeletal muscle cells.
The concentration of calcium helps in the contraction and relaxation of muscles. During depolarization, the calcium concentration increases that change conformation of troponin and tropomyosin and allows the actin to bind with myosin, resulting into relaxation of the muscle cell.
Hence, the correct option is "B. muscle relaxation".