Which Option Describes the Two Basic Components of Sourcefire Snort

Which option describes the two basic components of Sourcefire Snort rules?

A) preprocessor configurations to define what to do with packets before the detection engine sees them, and detection engine configurations to define exactly how alerting is to take place
B) a rule statement characterized by the message you configure to appear in the alert, and the rule body that contains all of the matching criteria such as source, destination, and protocol
C) a rule header to define source, destination, and protocol, and the output configuration to determine which form of output to produce if the rule triggers
D) a rule body that contains packet-matching criteria or options to define where to look for content in a packet, and a rule header to define matching criteria based on where a packet originates, where it is going, and over which protocol