The correct option is C Uterus of pregnant women
Smooth muscle is an involuntary non-striated muscle. Smooth muscle is found within the walls of blood vessels. Longest smooth muscle fibers are found in the walls of pregnant uterus where they may reach a length of 500mm. The smooth muscles fibers are usually arranged in the form of sheet or bands. Sarcolemma: The cell membrane of each smooth muscle fiber is called sarcolemma