A radiograph of an AP axial L5/S1 projection reveals that the jt space is not open. The following factors were used on this female patient: 80 kV, 40 SID, grid, 35 caudal, and CR centered to ASIS. Which of the following factor needs to be mod to produce a more diagnostic image?
a. Increase the CR angle
b. Decrease the CR angle
c. Change the direction of the CR angle
d. Center the CR higher to place it parallel to the jt space