The formation of `(B)` and `(D)` takes place, respectively, when `:`
A. The formation of `(B)` occurs by anti`-` and `(D)` by syn`-` addition of `H_(2)`.
B. The formation of `(B)` occurs by syn`-` and `(D)` by anti `-` addition of `H_(2)`.
C. The formation of both takes place by syn `-` addition of `H_(2)`.
D. The formation of both takes place by anti `-` addition of `H_(2)`.
