Which of the following is NOT a reason to expose radiographs on an edentulous patient?

a. To establish the position of anatomical structures prior to implants
b. To assess the density of tori
c. To determine the quality and condition of alveolar bone
d. To detect retained root tips or impactions

b. Tori are benign tumors consisting of a localized overgrowth of bone. While not present in all patients, tori are considered normal.