On the "slow" setting, a fan rotates 100 times in 1 minute. The rate of rotation doubles on the "medium" setting, and doubles again on the "high" setting. How many times will the fan rotate in 15 minutes on the "high" setting?
(A) 3000
(B) 1500
(C) 6000
(D) 4500
(E) 60000
Since the rate of rotation of the fan doubles between the slow and medium settings and the fan rotates 100 times in 1 minute on the slow setting, then it rotates $2 \times 100=200$ times in 1 minute on the medium setting.

Since the rate of rotation of the fan doubles between the medium and high setting, then it rotates $2 \times 200=400$ times in 1 minute on the high setting. Therefore, in 15 minutes, it will rotate $15 \times 400=6000$ times.

Answer: (C)