Question: For a TDD-TDD band pair in E-UTRA, what condition requires a UE to support at least one of srs-FlexibleTiming-r14 and/or srs-HARQ-ReferenceConfig-r14?
Option 1: When the band pair's rf-RetuningTimeDL-r14 or rf-RetuningTimeUL-r14 exceeds 1 OFDM symbol.
Option 2: When the UE operates in a specific frequency range (e.g., FR1).
Option 3: During handover from LTE to another radio access technology.
Option 4: For all TDD-TDD band pairs, regardless of retuning times.
Explanation: This is correct because for a TDD-TDD band pair, if either the downlink or uplink radio frequency retuning time exceeds 1 Orthogonal Frequency Division Multiplexing (OFDM) symbol, the User Equipment (UE) must support at least one of srs-FlexibleTiming-r14 or srs-HARQ-ReferenceConfig-r14 to ensure efficient handling of retuning times in TDD-TDD band pairs.