(a) Concave mirror as well as convex lens

(b) Convex mirror as well as a concave lens

(c) Two plane mirrors placed at 90° to each other

(d) Concave mirror as well as a concave lens

Answer: (d) Concave mirror as well as a concave lens

Explanation: Concave mirror and concave lens can make a parallel beam of light when light from a point source is incident on it.