Final answer:
The gluteus maximus and hamstrings are responsible for extending the hip when the leg accepts weight during initial contact.
Step-by-step explanation:
The muscles that play a role in extending the hip as the leg begins to accept weight at initial contact are the gluteus maximus and the hamstrings. The gluteus maximus is the largest and most superficial of the gluteal muscles and is primarily responsible for the extension of the thigh at the hip joint. The hamstrings, which are located at the back of the thigh, also play a significant role in hip extension.
The rectus femoris, although it can aid in hip flexion, is primarily a knee extensor and is not involved in hip extension. Similarly, the gluteus medius primarily abducts the femur at the hip, rather than extending it. Therefore, the correct answer is C. Hamstrings and gluteus maximus.