Question: What is a prerequisite for a User Equipment (UE) to indicate support for `ce-CSI-RS-FeedbackCodebookRestriction-r16` when operating in coverage enhancement mode A?
Option 1: The UE must operate exclusively in TDD (Time Division Duplexing) mode.
Option 2: The UE has to be capable of transmitting on multiple CSI-RS (Channel State Information Reference Signal) resources simultaneously.
Option 3: The UE needs to support a specific modulation scheme, such as 256-QAM.
Option 4: The UE must also indicate support for `ce-CSI-RS-Feedback-r16`.
Explanation: For a UE to indicate support for codebook subset restriction for CSI-RS-based feedback in coverage enhancement mode A, it is mandatory that the UE also supports CSI-RS-based feedback in this mode. This ensures proper utilization and restriction of codebooks for enhanced feedback under specific coverage conditions.