Why Do Your Parents or Grandparents Most Likely Need Glasses

Why do your parents or grandparents most likely need glasses to read?

A) The optic nerve sends signals more slowly as people age.
B) They have spent more time reading books at close range than have younger people.
C) The lens of the eye stiffens with age, making it difficult to focus on nearby objects.
D) The lens of the eye becomes rounder with age.
E) The photoreceptors of the eye are no longer as responsive.