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 and is in motion with an upward velocity of magnitude $v$ . A uniform magnetic field is present, directed downward as shown. The direction of the induced current through the resistor $R$ is

A) from $b$ to $a$ .
B) from $a$ to $b$ .
C) No current is induced.