IV.A.57. If a 400 speed radiographic receptor is replaced with a 200 speed receptor approximately the same film density would be obtained if:
a. The MAS is changed from 100 MAS to 50 MAS.
b. The KV is changed from 50 KV to 100 KV.
c. The focal spot-receptor distance is changed from 72 inches to 40 inches.
d. The film processing temperature is increased as necessary.