Question: What is the primary purpose of introducing "comfort tones" by a Public Land Mobile Network (PLMN) during call connection?
Option 1: To provide entertainment to callers before the call is established
Option 2: To indicate to the user that their call is progressing, preventing premature termination
Option 3: To announce promotional offers from the PLMN operator
Option 4: To mask background noise on the caller's end
Explanation: The correct answer, Option 2, highlights the main intention behind using comfort tones - to reassure the caller that the call setup process is ongoing, thus reducing the likelihood of the caller hanging up too early. This aligns with the telecom concept of enhancing user experience through subtle yet effective measures during session establishment.