Read the following announcement and mark the letter A, B, C, or D on your answer sheet to indicate the correct option that best fits each of the numbered blanks from 13 to 16

AT THE AIRPORT ANNOUNCEMENT
1. Passengers are expected to check in ___(1)___ two hours prior to departure time to avoid delays.
2. Please bring ___(2)___ carry-on bag that fits in the overhead compartment.
3. It is essential to follow airport staff's instructions ___(3)___ for your own safety.
4. Late arrivals will not be accommodated, so please arrive at the boarding gate ___(4)___.