In the heart, an action potential starts at the sinoatrial (SA) node. It is then conducted by the following components: (1). purkinje cells, (2). AV bundle, (3). AV node, (4). bundle branches. What is the correct order of conduction?
A. 3, 4, 2, 1
B. 1, 3, 2, 4
C. 4, 3, 2, 1
D. 3, 2, 4, 1
E. 2, 3, 1, 4
