Question: When an MRFC receives an SDP offer with media-level "a=imageattr" and supports image size negotiation, what action(s) must the MRFC take regarding resource seizure/modification and SDP answer on the Mr interface?
Option 1: Ignore the received image attributes and return a basic SDP answer.
Option 2: Include only the "recv" keyword with supported image sizes in the SDP answer.
Option 3: Modify resources in the MRFP without including image attribute parameters.
Option 4: Include generic image attribute parameters for send and receive directions when seizing/modifying resources, and include the "a=imageattr" with supported image sizes in the SDP answer.
Explanation: This is because, if the MRFC supports image size negotiation and receives an SDP offer with "a=imageattr", it must both include generic image attribute parameters for send and receive directions when interacting with the MRFP (for resource seizure/modification) and reflect the supported image sizes in the SDP answer on the Mr interface to ensure compatibility and effective media transmission, aligning the MRFC and MRFP on image sizes for optimal video communication.