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 $v$ . What is the polarity of the induced emf in terminals $X$ and $Y$ ?

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