Impulses from SA node to the left atrium and AV node passes through:: (A) Bundle of His, (B) Bachmann bundle, (C) Purkinje fibres, (D) None
Answer is B. There are three bundles of atrial fibers that contain Purkinje-type fibers and connect the SA node to the AV node: the anterior, middle (tract of Wenckebach), and posterior (tract of Thorel) tracts.
Bachmann bundle is sometimes used to identify a branch of the anterior internodal tract that connects the right and left atria. 
 
Key Concept
3 INTERNODAL TRACTS:
Connects SA node to AV node:

Anterior – Bachman’s bundle
Middle – Wenckebach’s bundle
Posterior – Thorel’s bundle

Reference: Ganong’s Review of Medical Physiology T W E N T Y - F I F T H   E D I T I O N page no 519