Which Step of Impulse Conduction Is Most Conducive to Atrial

Which step of impulse conduction is most conducive to atrial kick?

A) The firing of the sinoatrial node, which results in atrial depolarization
B) The conduction delay at the AV node, allowing time for filling
C) Conduction through the bundle of His, enhancing ventricular depolarization
D) Conduction to the Purkinje fibers, allowing for ventricular contraction