Question: What is a prerequisite for a User Equipment (UE) to support the `pur-CP-L1Ack-r16` feature in E-UTRA, specifically regarding core network (CN) support?
Option 1: The UE must support only `ce-ModeA-r13` for both TDD and FDD.
Option 2: The UE must also support either `pur-CP-EPC-r16`, `pur-CP-5GC-r16`, `pur-CP-EPC-CE-ModeA-r16`, or `pur-CP-5GC-CE-ModeA-r16`.
Option 3: There are no additional CN support requirements for UEs to support `pur-CP-L1Ack-r16`.
Option 4: The UE must exclusively operate in FDD mode with a `ue-Category-NB` configuration.
Explanation: For a UE to support the `pur-CP-L1Ack-r16` feature, which pertains to PUR Layer1 acknowledgement, it is mandatory that the UE also indicates support for at least one of the specified core network (CN) capabilities: `pur-CP-EPC-r16`, `pur-CP-5GC-r16`, `pur-CP-EPC-CE-ModeA-r16`, or `pur-CP-5GC-CE-ModeA-r16`. This ensures seamless integration and functionality across both radio access and core network aspects for UEs that also support `ce-ModeA-r13` or specific FDD configurations with `ue-Category-NB`.