Alpha Can Produce Either 18 Oranges or 9 Apples an Hour

Alpha can produce either 18 oranges or 9 apples an hour, while Beta can produce either 16 oranges or 4 apples an hour. Which of the following terms of trade between apples and oranges would allow both Alpha and Beta to gain by specialization and exchange?

A) 1 orange for 0.2 apples
B) 2 apples for 3 oranges
C) 3 apples for 3 oranges
D) 1 apple for 3 oranges