Question: What happens to the HARQ entity when an SCell is removed during a MAC reconfiguration?
Option 1: The HARQ entity is reset.
Option 2: The HARQ entity remains unchanged.
Option 3: The corresponding HARQ entity is removed.
Option 4: A new HARQ entity is initialized.
Explanation: When an SCell is removed during a MAC reconfiguration, the MAC entity removes the corresponding HARQ entity to reflect the change in the cell configuration. This ensures that the MAC entity's operation aligns with the updated cell setup.