According to the Center for Veterinary Research, once someone is bitten by an animal infected with rabies, the chances of contracting rabies depends on how deep the bite is, how far it is from the head, and how advanced the virus was in the infected animal.

How would this evidence support the main idea that not everyone bitten by a rabid animal will contract rabies?
A. by showing that several factors work together to determine whether someone will contract rabies
B. by showing that doctors are not certain which factors control whether someone will contract rabies
C. by showing that only one factor is important when determining whether someone will contract rabies
D. by showing that nearly everyone bitten by rabid animal will eventually contract rabies