Select the TRUE statement from the choices given.

a. Because of the boundary effect, a 10–12% density change is visually perceptible.
b. An AP projection of the knee demonstrates the patella posterior to the femur.
c. Visual acuity is improved in low-light conditions.
d. Pattern recognition is very intensely studied as part of a radiologist's education.

d. Pattern recognition is very intensely studied as part of a radiologist's education.