optics question?

Question

if an object moves closer to a lens, the focal point changes. Both cameras and the human eye need to adjust their focus for objects that are closer or farther away, but they do it in different ways. How do they do it?
(pick the correct answer)
a) The human eye is able to move the lens forward or backwards slightly, changing the focal length. In a camera, the lens changes shape when you push the focus button.
b) The human eye changes the shape of the lens and the camera moves the lens forward or backward
c) the human eye is able to move the lens forward or backwards slightly, changing the focal length. In a camera, the diaphragm opens and closes to change the focal length.
d) Cameras focus by changing the lens that light passes through. The human eye focuses by changing the shape of the lens

Answer 1

It is true, that the focal distance of an eye lens can change.
Only answer B is alright.

Th

Answer 2

I vote for b.

Answer 3

http://en.wikipedia.org/wiki/Eye
http://en.wikipedia.org/wiki/Camera

Answer 4

I believe it is "C" but this is only a guess