Question: What is a prerequisite for a User Equipment (UE) to support the configuration defined by the `secondSlotStartingPosition-r13` field in an Evolved Universal Terrestrial Radio Access Network (E-UTRA)?
Option 1: The UE must support uplink Carrier Aggregation (CA).
Option 2: The UE is operating in a Time Division Duplexing (TDD) mode.
Option 3: The UE supports downlink Licensed Assisted Access (LAA) operation.
Option 4: The UE has enabled Dual Connectivity (DC) with at least two cells.
Explanation: The correct answer is Option 3 because the `secondSlotStartingPosition-r13` field's applicability is contingent upon the UE supporting downlink LAA operation, indicating that for a UE to utilize this setting, it must first have downlink LAA capability.