Which of the following can make a parallel beam of light from a point source incident on it?

Q Which of the following can make a parallel beam of light from a point source incident on it?

A.            concave mirror as well as convex lens

B.            convex mirror as well as concave lens

C.            two plane mirrors placed at 90degree to each other

D.            concave mirror as well as concave lens

Answer: concave mirror as well as convex lens