Final answer:
Skeletal muscle is referred to as striated muscle due to its striped appearance under a microscope, which is a result of the arrangement of contractile proteins. It is also called voluntary muscle as it can be consciously controlled. Therefore, the correct answer to the question is B. striated muscle.
Step-by-step explanation:
Skeletal muscle is referred to as striated muscle because of its appearance under a microscope, where it shows a striped or striated pattern. This pattern results from the arrangement of contractile proteins, specifically the actin and myosin, within the muscle fibers.
Unlike smooth muscle, which is found in the walls of hollow organs and is not under voluntary control, and cardiac muscle, which is found only in the heart and also operates involuntarily, skeletal muscle is under voluntary control and is involved in moving bones and skin. It is because of this volitional control mechanism that skeletal muscle is also called voluntary muscle. Therefore, the correct answer to the question is B. striated muscle.