This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Radiology
Optium phase for cardiac and coronary vessel imaging are 
Select and explain. 
A. Early systole, B. Mid-diastole, C. Early diastole, D. Late diastole
B: Mid-diastole
Answer: B: Mid-diastole 
Explanation: Optimum phase for cardiac and coronary vessel image is 

Mid-diastole at low or intermediate heart rates.
Late-systole - at high heart rates.