Question: In an SC (Short Message Service Center) supporting trigger SMS filtering for Tsms submissions, what is the primary purpose of comparing the SME (Short Message Entity) in the RP-OA field against a list of known SMEs?
Option 1: To prioritize messages from trusted SMEs for faster delivery
Option 2: To apply different billing rates based on the originating SME
Option 3: To filter and block short messages not originating from trusted SMEs
Option 4: To encrypt messages only from unknown SMEs for added security
Explanation: The primary purpose of this comparison is to ensure security and prevent spam or malicious messages. By filtering out messages that do not originate from trusted Short Message Entities (SMEs), the SC can block potential threats, thus protecting the network and its users.