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: Physiology
The cardiac output can be determined by all except 
Select and explain. 
A. Fick's principle, B. V/Q ratio, C. Echocardiography, D. Thermodilution
B: V/Q ratio
Answer: B: V/Q ratio 
Explanation: Methods to determine the Cardiac output

Flowmeter
Cardiometer

-        Indirect method- Used in humans

Fick’s principle method
Indicator dilution method
Thermodilution method
Doppler echocardiography
Cineradiography