Which of the following optical devices can be used to produce a parallel beam of rays from a point source of light?
(A) Convex lens
(B) Concave lens
(C) Concave mirror
(D) Convex mirror
1
Both (A) and (B)
2
Both (A) and (C)
3
Both (A) and (D)
4
Both (B) and (C)