Induced emf is larger when the bar magnet moves faster through the coil. Which of the following best explains the physics behind it?
A. The magnetic field is larger inside the coil.
B. The direction of the magnetic field changes as magnet moves faster.
C. Induced emf is proportional to the strength of the magnet.
D. The rate of change of magnetic flux is larger when magnet moves faster.
E. None of the above