As Dr Levy Is Looking at an X-Ray of Bones

As Dr Levy is looking at an X-ray of bones in 20-year-old Jabu's leg, his comment, ____, would indicate that Jabu has reached skeletal maturity.

A) 'I see that this is the longest your leg bone will ever be'
B) 'I see excessive encapsulation'
C) 'I see a significant decrease in density'
D) 'I see very little plaque'