Final answer:
C) Message. Spam filters use keywords and message patterns to identify and block spam emails, protecting users from unwanted content and security threats.
Step-by-step explanation:
Spam filters search for spam by watching for keywords and by monitoring suspicious message patterns and frequencies. When filters identify unusual or repeated patterns that are characteristic of spam emails, such as certain phrases, urgent language, or deceptive links, they can flag these messages as potential spam.
Algorithms and machine learning techniques can also be used to predict and identify spam messages by analyzing large datasets to discern common spam characteristics. By doing this, spam filters help protect users from unwanted email content, potential scams, and phishing attempts.