As Shown in the Figure,a Metal Bar Is in Contact

Multiple Choice

As shown in the figure,a metal bar is in contact with a pair of parallel rails.A steady,uniform,magnetic field B is present directed to the right.The bar is moving upward with velocity of magnitude ν.What is the polarity of the induced emf in terminals X and Y?

A) X and Y are at the same potential.
B) X is positive and Y is negative.
C) Y is positive and X is negative.