Hello Nicole,

When I do this question I see that it is asking about what the advantage of the doppler ultrasound is. I know that the doppler effect is the shift in frequency of sound waves as a source moves from the observer. So next I go to the passage and find information about the differences in the two types of ultrasound. This sentence specifically leads me to choose B:

"The resulting image of blood flow around and through the heart allows an accurate diagnosis of the patient’s circulatory system"

Here are my thoughts for the answers:

A) this is what a normal US does - however the passage talks more about blood flow, and circulation
B) Correct Answer
C) the passage doesn't focus on tissue density
D) the passage does not focus on heart wall thickness