Which of the following statements about conducting system of the heart is INCORRECT ?
I. Mass of nodal tissue seen in the lower-left corner of the right atrium is the sinoatrial node.
II. The nodal musculature can generate action potentials only in response to external stimuli .
III. The number of action potential that could be generated in a minute varies at different parts of the nodal system .
IV. The SAN can generate the maximum number of action potential , i.e., 80-85 `min^(-1)`

Options

A. I, II , III and IV
B. I, II and IV
C. II, III and IV
D. I,II and III

Answer

B