Choice C. Choice A.
Work Step by Step
The magnetic field near a long, current-carrying straight wire is inversely proportional to the distance from the wire. Loop C stays at the same distance from the wire. The magnetic flux through the loop remains constant and no current is induced. For loop D, the magnetic field at the loop due to the current in the straight wire is into the page. As loop D is pulled away, the magnitude of the flux decreases because it is moving into a region of weaker magnetic field. In an attempt to keep the flux from changing, a clockwise current is induced which creates more magnetic field into the page.