As a Pediatric Nurse, You Notice a Child Using His

As a pediatric nurse, you notice a child using his or her arm muscles with great difficulty for assistance when rising from a supine position. It is suspected that this child is suffering from muscular dystrophy. Which of the following procedures can be used to confirm the decreased production of the protein dystrophin and subsequent infiltration of fatty material into the muscle areas?

A) Muscle biopsy
B) MRI of lower extremities
C) Serum protein evaluation
D) Urine protein evaluation