How is a right bundle branch block (RBBB) distinguished from a left bundle branch block (LBBB)?

A. Monitor leads V1 to V6 and measure the PR interval
B. Monitor lead V1. If the majority of the ventricular depolarization is positively deflected, it is LBBB; if the QRS is negative, it is RBBB
C. Monitor lead V1. If the majority of the ventricular depolarization is positively deflected, it is RBBB; if the QRS is negative, it is LBBB
D. Monitor leads I, II, and III and observe the P wave configuration

Answer: C