Question: What is the requirement for mobile station support for PBCCH and PCCCH in A/Gb-mode of operation?
Option 1: Mandatory, as specified in other 3GPP specifications.
Option 2: Optional, but the network can enable or disable it.
Option 3: Mandatory, and the network must always enable it.
Option 4: Optional, and the network shall never enable it.
Explanation: According to the specification, mobile station support for PBCCH and PCCCH is optional in A/Gb-mode of operation. Moreover, the network is not allowed to enable these channels, making their use obsolete in this mode.