Question: What happens to the HARQ buffers for all serving cells when the timeAlignmentTimer associated with the pTAG expires?
Option 1: They are flushed.
Option 2: They are cleared.
Option 3: They are released.
Option 4: They remain unchanged.
Explanation: According to the specification, when the timeAlignmentTimer associated with the pTAG expires, the MAC entity flushes all HARQ buffers for all serving cells. This is a specific action taken by the MAC entity in response to the timer expiration, and it ensures that any pending data in the buffers is cleared out.