Assertion (A): SAN is called the pacemaker of the heart.
Reason (R): It generates the maximum number of action potentials and hence, it sets the pace of heart beat.
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.