Consider two concentric spherical metal shells of radii `r_(1)` and `r_(2) (r_(2) gt r_(1))`. If the outer shell has a charge q and the inner one is grounded, then the charge on the inner shell is
A. `(-r_(2))/r_(1) q`
B. zero
C. `(-r_(1))/r_(2) q`
D. `-q`