Officer Castro Notices a Car in Front of Him Driving

Multiple Choice

Officer Castro notices a car in front of him driving at a slow speed.  The driver seems to be driving erratically. Officer Castro activates his blue lights and attempts to pull the car over.  The driver continues to drive for approximately two additional miles before pulling over.  When Officer Castro slowly approaches the car, he smells what seems to be a heavy odor of marijuana.  The driver has dilated eyes and slurred speech.  There are four individuals in the car.
When Officer Castro pulled the car over after suspicious behavior, he encountered a strong smell of a well-known drug that he has had significant experience with prior to this case.  The strong presence of the smell of this drug gives Officer Castro enough ________ to search the vehicle.

A) reasonable suspicion
B) hunch
C) probable cause
D) proof beyond a reasonable doubt