A radiologist is able to evaluate the movement of body organs. What type of radiological procedure is being used?

A. Ultrasound
B. Fluoroscopic examination
C. Magnetic resonance imaging
D. Film Survey

I'm assuming it's A. Ultrasound because that's the only procedure I know of that can see movement. Am I wrong?

I think there's a better answer.

http://www.umm.edu/radiology/fluroscopy.htm