At a minimum, probable cause for an arrest can be said to exist when a police officer has:

Question

a. a mere hunch that a particular person has committed a crime

b. more than a mere hunch but less than the level of proof needed for a conviction

c. the level of proof known as proof beyond a reasonable doubt

d. the level of certainty that makes it more likely than not that the subject has committed a crime

e. a reasonable basis to suspect that criminal activity may be afoot

Answer 1

a reasonable basis to suspect criminal activity based on skills training and experience.

Answer 2

None of your answers accurately depict probable cause.  To have probable cause the officer needs to have evidence that a crime was committed and evidence supporting that the person they are arresting was the most likely suspect to have committed the crime.  However, to prove someone guilty of a crime in court, the prosecution must have your C answer which is proof beyond a reasonable doubt.