Question

A concave lens always gives a virtual image. In optical lenses(for eye defects) worn by humans which of the following statements is true?
a) The lenses can never be concave.
b) In some cases the lens can be concave if the focal length is much larger than 2.5 cm.
c) All focal length concave lenses are possible.
d) All focal length convex lenses are possible.

Answer 1

C is the correct answer

Answer 2

But whyy???