An overweight 13-year-old male presents with a 3-week history of right lower thigh pain. he first noticed the pain when jumping while playing basketball, but now it is present even when he is just walking. on examination he can bear his full weight without an obvious limp. there is no localized tenderness, and the patella tracks normally without subluxation. internal rotation of the hip is limited on the right side compared to the left. based on the examination alone, which one of the following is the most likely diagnosis?

a. avascular necrosis of the femoral head (legg-calvé-perthes disease)
b. osteosarcoma
c. meralgia paresthetica
d. pauciarticular juvenile rheumatoid arthritis
e. slipped capital femoral epiphysis