Answer:
8,000 Oppenheimer and 12,000 Natural resources
Step-by-step explanation:
as is said, the fund Oppenheimer is the one who has given the highest return (15%), so the key here is trying to find the highest participation in this fund, but as said too there is a constrarin, and it is the maximun amount invested in oppenheimer (8,000).
So as Oppenheimer is the fund with highest return, we must invest all posible, so the investment will be 8,000. As the total amount is 20,000 using difference is possible to know that the investment in natural resources will have a total amount of 12,000, it respect the other option.