A combination of two thin lenses with focal lengths `f_(1)` and `f_(2)` respectively forms and image of distant object at distance `60cm` when lenses are in contact. The position of this image shifts by `30 cm` towards the combination when two lenses are separated by `10 cm`. The corresponding values of `f_(1)` and `f_(2)` are

A. 30 cm, -60 cm

B. 20 cm, -30 cm

C. 15 cm, -20 cm

D. 12 cm, -15 cm