What is the primary operational objective and benefit of implementing Controller-Pilot Data Link Communications (CPDLC) in en-route and oceanic airspace like Bahrain ACC?

1. To provide in-flight internet streaming to passenger cabin entertainment systems
2. To reduce voice radio frequency congestion, eliminate voice readback/hearback misunderstandings, and enable direct textual transmission of ATC clearances and route revisions
3. To allow controllers to remotely take over manual aircraft flight control surfaces
4. To automatically calculate passenger baggage fees during cruising flight