Question: In a TDD system, when can an Enhanced Transport Format Combination (E-TFC) selection be performed by the User Equipment (UE)?
Option 1: During any Radio Resource Control (RRC) state
Option 2: Only in the CELL_FACH (Forward Access Channel) state
Option 3: Exclusively when transitioning from CELL_DCH to CELL_FACH
Option 4: Only in the CELL_DCH (Dedicated Channel) state
Explanation: E-TFC selection involves intricate power calculations, including maximum UE transmission power and E-PUCH transmission power. This process is only allowed in the CELL_DCH state, where a dedicated channel is established, ensuring stable and sufficient resources for such computations and transmissions, maintaining efficient resource use and optimal network performance.