[单选题]
The primary of a transformelr gk cwrbof 2ni3(f zh./v--:r has 100 turns and its secondao/3adn*2cgyl h+nr(nkh . cb+ry has 200 turns. If the input voltage to the primary is 100 2a3dh*kl(gc bnon. ++nyhc/r V, we can expect the output voltage of the secondary to be
A. 50 V.
B. 100 V.
C. 200 V.
D. none of the given answers
