The correct option is
A The Cell membrane that encloses each muscle cell, specifically muscle cells
Sarcolemma is the name of the cell membrane that encloses each muscle cell, specifically muscle cells
The sarcoplasmic reticulum is a specialized type of smooth ER that regulates the calcium ion concentration in the cytoplasm of striated muscle cells.
The endoplasmic reticulum is a network of membranous tubules within the cytoplasm of a eukaryotic cell.