Question: What is the primary purpose of having at least two Short Message Service Control (SMC) entities per service type in a Mobile Station (MS) supporting Short Message Service?
Option 1: To enable simultaneous sending and receiving of short messages over different networks (e.g., GSM and GPRS).
Option 2: To allow the MS to receive Mobile Terminated (MT) messages while transferring a Mobile Originated (MO) message, and vice versa.
Option 3: To increase the storage capacity for incoming short messages when the MS is in idle mode.
Option 4: To enhance the security of short message transmissions by using one SMC for encryption and another for decryption.
Explanation: Having at least two SMC entities per service type in an MS ensures that it can handle both incoming (MT) and outgoing (MO) short messages simultaneously, preventing conflicts or blocked transfers when a message is being sent while another is being received. This setup is crucial for uninterrupted Short Message Service functionality.