Concept:Contraction of the ciliary muscles changes the curvature of the eye lens so that the eye can focus on close objects.
Explanation:The eye lens is held in position by suspensory ligaments, which are attached to the ciliary muscles.
When the ciliary muscles contract, these suspensory ligaments become loose and relaxed, not tight.
This reduces the outward pull on the lens.
Because the lens is elastic, it then bulges and becomes thicker.
This thicker shape makes the lens more convex (more rounded).
A more convex lens has greater refractive power and therefore a shorter focal length.
This allows the eye to clearly focus light from nearby objects onto the retina.
So, the lens does not become more concave, and its focal length does not increase.
Answer:The correct option is B: the lens becomes more convex.