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. The opportunity cost of producing 1 orange for Alpha and Beta, respectively, are:

A) 0.25 apples; 0.5 apples.
B) 9 apples; 4 apples.
C) 0.5 apples; 0.25 apples.
D) 2 apples; 4 apples