If OA=a, OB=b, OC=c are the co-terminus edges of regular parallelopiped, then the shortest distance between the diagonal and the side OB not meeting the diagonal is

A. `(bc)/sqrt(b^(2) + c^(2))`

B. `(ca)/sqrt(c^(2) + a^(2))`

C. `(ab)/sqrt(a^(2) + b^(2))`

D. `(abc)/sqrt(a^(2) + b^(2) + c^(2))`