The correct answer is C. Stomach.
Smooth muscles are involuntary muscles that are found in the walls of hollow organs, such as the stomach, intestines, bladder, and uterus. They are also found in the blood vessels and airways. Smooth muscles are controlled by the autonomic nervous system, which means that we do not consciously control them.
The muscles of the legs and arms are skeletal muscles. Skeletal muscles are voluntary muscles that are attached to bones and allow us to move our bodies. Skeletal muscles are controlled by the somatic nervous system, which means that we consciously control them.
The heart is a muscle, but it is a special type of muscle called cardiac muscle. Cardiac muscle is striated, like skeletal muscle, but it is also involuntary, like smooth muscle. Cardiac muscle is controlled by the autonomic nervous system.
In conclusion, smooth muscles are likely to be found in the stomach.