Use Lenz’s law to find the sense of induced current

The magnetic field is into the plane and its magnitude is increasing with time.

By Lenz’s law, the induced current must oppose this increase, so it must produce a magnetic field out of the plane.

A current that produces magnetic field out of the plane is anticlockwise.

Therefore, in the loop:

• on the left vertical branch, current flows upward,
• on the right vertical branch, current flows downward.

Hence,

• in segment $ab$, current is in the direction $ab$,
• in segment $cd$, current is in the direction $dc$.

So the directional statement in Option D is correct, while Option C is incorrect.

Compare magnitudes $I_1$ and $I_2$

Since the arrangement is one closed conducting loop, the induced current circulates around the loop. In a series loop, the same current passes through all segments.

Therefore, the magnitudes of current in segments $ab$ and $cd$ are equal: $I_1 = I_2.$

So:

• Option A ($I_1 > I_2$) is false,
• Option B ($I_1 < I_2$) is false.

Final answer

The only correct option is: $\boxed{D}$