Question: What is a prerequisite for a User Equipment (UE) to include the `powerClassNB-14dBm-r14` field in its radio access capabilities, specifically for Narrowband Internet of Things (NB-IoT) across all supported bands?
Option 1: The UE must support all frequency bands defined for E-UTRA.
Option 2: The UE must not include the `powerClassNB-20dBm-r13` field in its capabilities.
Option 3: The UE has to be capable of transmitting at a minimum of 23 dBm for LTE.
Option 4: The UE needs to support Voice over LTE (VoLTE) services.
Explanation: This is correct because, according to the specifications, for a UE to include the `powerClassNB-14dBm-r14` field (indicating support for power class 14 dBm in NB-IoT), it must not already include the `powerClassNB-20dBm-r13` field. This ensures compatibility and clarity in the UE's power class capabilities for NB-IoT across all its supported bands, avoiding potential conflicts between different power class specifications.