Here's a problem to solve: Which is the best explanation for how air masses move across the United States?

Among the 4 following options, which is the correct answer?

- A: The prevailing westerlies move air masses from west to east across the United States but may be deflected by the jet stream.
 
- B: The trade winds move air masses from west to east across the United States.
 
- C: The jet stream moves air masses from the Pacific Ocean across the United States.
 
- D: The warm air of the Gulf Stream causes air masses to move from the Atlantic Ocean to the Pacific Ocean.
 