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
ECG with "mean" axis of 90deg. In which lead there would be the maximum voltage of R wave? 
Select and explain. 
A. III, B. I, C. aVF, D. aVL
C: aVF
Answer: C: aVF 
Explanation: Ans. C. aVF90deg cardiac axis corresponds straight to lead aVF and hence as such maximum 'It' wave amplitude would be seen in that lead only.