A converging lens of focal length `f_(1)` is placed in front of and coaxially with a convex mirror of focal length `f_(2)`. Their separation is d. A parallel beam of light incident on the lens returns as a parallel beam from the arrangement, Then,

Options

A. The beam diameters of the incident and reflected beams must be the same
B. `d=|f_(1)|-2|f_(2)|`
C. `d=|f_(1)|-|f_(2)|`
D. If the entire arrangement is immersed in water, the conditions will remain unaltered