Which of the following is NOT a disadvantage of the paralleling technique?

a. The best images are obtained with the more difficult to position long 16-inch PID.
b. Image receptor positioning is difficult for patients with small mouths.
c. There is a limited number of image receptor holders that accommodate the paralleling technique.
d. It is more likely to excite an exaggerated gag reflex to achieve parallel position in the posterior region.

c. There are many choices of image receptor holders on the market with external aiming devices specifically designed to make paralleling simple and easy to learn.