Rationale:
Rhabdomyosarcoma is an aggressive malignant tumor found in children, primarily originating from striated (skeletal) muscles.

This cancer is associated with the muscles that facilitate the body’s voluntary movements such as walking, moving limbs, and maintaining posture.

In children, this tumor is often found in the head-neck region, genitourinary tract, and extremities, as skeletal muscle tissue is present in these locations.

The cerebrum is composed of nervous tissue, the kidney is a visceral organ, and tendons are connective tissue; therefore, these are not the origin of Rhabdomyosarcoma.

Thus, the correct answer is striated muscles.