Question: What is the primary purpose of the '3GPP-Adaptation' header field in PSS (Transparent end-to-end Packet-switched Streaming Service), as implemented by PSS servers and clients?
Option 1: To enable dynamic adjustment of bit-rate adaptation parameters for optimizing media streaming quality.
Option 2: To provide authentication credentials for secure access to streaming services.
Option 3: To specify the codec preferences for audio and video content.
Option 4: To indicate the client's preferred language for subtitles.
Explanation: The '3GPP-Adaptation' header is defined to enable PSS clients to set bit-rate adaptation parameters, which directly relates to optimizing media streaming quality by allowing adjustments to buffer size and target time for interrupt-free playback.