What Is the Average Induced EMF Between the Ends of the Wings

Multiple Choice

What is the average induced EMF between the ends of the wings of a plane flying at a speed of 500 km/hr when the vertical component of Earth's magnetic field is 3 $\times$ 10^-5 T? The distance between the wingtips is 25 m.

A) 0.20 V
B) 0.050 V
C) 6.0 V
D) 0.10 V
E) none of the above