The suggested answer is C.
Rule-based detection relies on predefined rules and patterns to identify specific actions or behaviors, whereas statistical detection involves analyzing data to determine the probability or likelihood of an action being a security threat. Therefore, the primary difference is that rule-based detection does not focus on the likelihood of an action, it simply matches actions to a set of predefined rules. Statistical detection, on the other hand, assesses the likelihood of an action occurring based on statistical analysis. Hence, the correct answer emphasizes the likelihood of a user's action.