The correct option is A 2 cm
The focal length of a normal and relaxed eye lens is about 2 cm because a normal eye has retina, 2 cm behind the eye lens and the image of object at infinity (relaxed view) is formed at retina.
So, the focal length of a normal eye lens is equal to the distance between the eye lens and retina, i.e. about 2 cm.
Hence, option (B) is the correct answer.