A radiograph of a PA axial projection for the intercondylar fossa does not demonstrate the fossa well. It is foreshortened. The following positioning factors were used: patient prone, knee flexed 40° to 45°, CR angled to be perpendicular to the femur, 40-inch SID, and no rotation of the lower limb. On the basis of the factors used, what changes need to be made to produce a more diagnostic image?
a. Reduce flexion of the knee to 20° to 30°
b. Rotate lower extremity 10° medially
c. Increase SID to at least 48 inches (123 cm)
d. CR must be perpendicular to lower leg