A physical therapist is treating a patient with back pain and notices the patient has a limp. The therapist suspects that the leg lengths may be unequal. The physical therapist wants to assess the leg lengths for any anatomical discrepancies. Which of the following is the MOST accurate method to determine if there is a true leg-length discrepancy?

A. Perform a supine to long sit test and monitor how the malleoli line up
B. Tape measure from umbilicus to lateral malleolus
C. Tape measure from ASIS to medial malleolus
D. Tape measure from umbilicus to medial malleolus