Which of the following is a term to describe a computerized, body scanning method that uses nuclear magnetic resonance instead of X-ray radiation. The patient is placed in a large circular magnet, which uses the magnetic field to measure activity of hydrogen atoms within the body. A computer translates that activity into cross-sectional images of the body.

A•Positron emission tomography (PET)
B•Computerized tomography (CT)
C•Ultrasonography
D•Magnetic resonance imaging (MRI)