Final answer:
B) 30 degrees cephalad
The angle for a Barium Enema sigmoid shot when the patient is prone is 30 degrees cephalad, aiding in appropriate visualization of the sigmoid colon.
Step-by-step explanation:
The angle of the Central Ray (CR) for a Barium Enema sigmoid shot if the patient is prone is 30 degrees cephalad. When performing a sigmoid shot during a Barium Enema procedure, it is necessary to angle the CR accordingly to visualize the anatomy adequately. The term 'cepahalad' indicates that the CR is directed towards the head from the base of the spine, which is the preferred angulation for this type of radiographic examination in a prone position.