Which of the following statements regarding managing occlusal radiograph exposures is FALSE?

a. Exposure factors are the same as those used for periapical and bitewing radiographs in the same region.
b. The open end of the PID should be positioned as close to the patient's skin as possible, without touching.
c. A modification of the paralleling technique is used to determine the vertical angulation.
d. A shorter PID minimizes distortion.

c. The vertical angulation for topographical occlusal radiographs follows the rules of the bisecting technique used for periapical radiographs, where the central rays of the x-ray beam are directed through the apices of the teeth perpendicularly toward the bisector.