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: Medicine
A female of 40 years presenting with intolerance to cold, constipation and hoarseness of voice was found to have cardiomegaly on chest roentgenogram. Which of the following investigations is the best to determine the cause of her careliomegaly? 
Select and explain. 
A. Coronary angiography, B. Left ventricular angiography, C. Right ventricular angiography, D. Echocardiography
D: Echocardiography
Answer: D: Echocardiography 
Explanation: None