Select the correct pathway for the transmission of impulses in the heart.

• A
  $SA$ node $\rightarrow$ $AV$ node $\rightarrow$ Purkinje fibers $\rightarrow$ $AV$ bundle
• B
  $AV$ node $\rightarrow$ $SA$ node $\rightarrow$ Purkinje fibers $\rightarrow$ $AV$ bundle
• C
  $SA$ node $\rightarrow$ $AV$ node $\rightarrow$ $AV$ bundle $\rightarrow$ Purkinje fibers
• D
  $AV$ node $\rightarrow$ $SA$ node $\rightarrow$ $AV$ bundle $\rightarrow$ Purkinje fibers