Answer: Option 'B' is correct.
Explanation:
Since we have given that
In case of Alpha:
Number of oranges = 18
Number of apples = 9
In case of Beta :
Number of oranges = 16
Number of apples = 4
We need to find the opportunity cost of producing 1 orange for Alpha and Beta.
Opportunity cost for Alpha is given by

Opportunity cost for Beta is given by

Hence, Opportunity cost for producing 1 orange for Alpha and Beta are 9 apples and 4 apples respectively.
Hence, Option 'B' is correct.