The converging point of incident beam is at the 20 cm from concave lens as shown in the figure are. The concave lens then moved away from convex lens with speed 1 $cm{s}^{-1}$ . The emergent ray from convex lens is

 

• A

  always converging at a single point

• B

  always diverging in nature

• C

  first converging then diverging

• D

  first diverging then converging