Answer:
C. a closed loop of wire moving at constant velocity in a nonuniform static magnetic field.
Step-by-step explanation:
As we know by Faraday's law that rate of change in magnetic flux will induce EMF
so mathematically we can say that

so we will have

so EMF will be induced if the flux linked with the closed loop will change with time.
So here correct answer will be
C. a closed loop of wire moving at constant velocity in a nonuniform static magnetic field.