Question

a diagnostic tool that uses powerful magnets to show images of the heart is
an electrocardiogram (ekg).
magnetic resonance imaging (mri)
an angiography.
a ct scan.

Explanation:

Magnetic Resonance Imaging (MRI) uses powerful magnets to create detailed images of the body, including the heart. A CT scan uses X - rays. An angiography involves injecting a contrast dye. An electrocardiogram (EKG) measures the electrical activity of the heart.

Answer:

magnetic resonance imaging (MRI)