Question: What is the primary purpose of the `+CAJOIN` action command in the context of User Equipment (UE)?
Option 1: To initiate a new voice group call to multiple recipients.
Option 2: To reject an incoming voice broadcast call with a specific reason.
Option 3: To query the current status of all ongoing voice calls.
Option 4: To accept an incoming or ongoing voice group or voice broadcast call.
Explanation: The `+CAJOIN` command is designed to accept an incoming or ongoing voice group or voice broadcast call, identified by parameters such as group identification and service type (e.g., voice group call or voice broadcast call), aligning with managing incoming calls in telecom networks, particularly those involving group communications.