A convex lens 'A' of focal length 20 cm and a concave lens 'B' of focal length 5 cm are kept along the same axis with a distance 'd' between them. If a parallel beam of light falling on 'A' leaves 'B' as a parallel beam, then the distance 'd' in cm will be:
(1) 30
(2) 25
(3) 15
(4) 50
(1) 30
(2) 25
(3) 15
(4) 50