Answer: c. beyond a reasonable doubt.
Explanation:
Beyond a reasonable doubt is the standard that is required to be met by the prosecution branch as an evidence in the criminal proceedings. This states that no other logical explanation can be drawn from the facts except in the situation where the defendant commits the crime, the defendant is considered to be innocent until proven guilty.
In the given situation, the state is required to prove the crime beyond a reasonable doubt as the Arthur is denying the crime that he has committed.