Answer:
The workers will only produce oranges.
Step-by-step explanation:
'Opportunity cost' is an important concept which shows the relationship between choice and scarcity. For example: One can spend money and time on one thing at a time but loses the opportunity do perform the other things, which would be his opportunity cost. Like you take a vacation for the money you have but the opportunity cost is not having a new car.
Relative price is the price of one commodity in terms of another. In the given situation, opportunity cost of an apple is 3 oranges and relative price of apple is 3, so the workers will produce only oranges, as it will be more profitable.