Dr. Perkins is a college professor. He is frustrated when students ask if text or lecture material will be covered on the next test. Dr. Perkins would prefer students to be interested in learning the material for its own sake rather than only being concerned about a grade. In other words, Dr. Perkins prefers his students to be motivated.
a) intrinsically
b) incentively
c) instinctively
d) extrinsically