Which Situation Is Least Likely to Present a Causation Issue

Which situation is least likely to present a causation issue?

A) An individual is shot in the back as he walks from a street fight and subsequently dies.
B) An ambulance, after having picked up a victim of a gunshot, crashes and the victim dies.
C) A gunshot wound victim dies after waiting for medical attention in a local emergency room for 4 hours.
D) A gunshot wound victim stumbles into the street and is hit by an oncoming vehicle and dies.