Why is a muscle cell different to a liver cell?

A muscle cell is a kind of cell that makes up an organism's muscle tissues. The muscles allow independent movement and regulate biological functions like digestion and heartbeat. These cells are specialized into distinct types based on their location and functions. All of them control movement by contracting, while much of this activity is involuntary, the muscles that direct the skeletal system can be consciously controlled. These muscles can be trained to carry out highly precise movements and strengthened through exercise. The liver cells secrete the bile, and this collects in the bile capillaries, which then unite, forming bile ducts. These bile ducts all eventually unite, forming the main hepatic duct, which gives a branch, the cystic duct, on its way toward the hepatic duct. The cystic duct leads into the gall bladder. Where a cystic duct joins the hepatic duct, the two continue as the general bile duct, which then joins the pancreatic duct, forming a common duct that opens into the duodenum...

Ithink the answer is d.