Which of the Following Best Explains Why Visual Acuity Declines

Which of the following best explains why visual acuity declines during middle age?

A) The lens of the eye enlarges and becomes less flexible and less transparent.
B) The occipital lobe,the area of the brain that controls vision,becomes less efficient.
C) The retina of the eye becomes less pliable and malleable,therefore affecting acuity.
D) The phenomenon known as binocular vision becomes less efficient and slowly disappears.