Two groups of people, the Yellow Group and the Orange Group, suddenly find themselves in a world where there are only two 'production opportunities': pumping water and picking berries. After a little while the Yellow Group has learned that it seems to produce about 2 gallons per hour while pumping water and about 8 berries per hour while picking.

Meanwhile the Orange Group has learned that it seems to produce about 1 gallon per hour while pumping water and about 3 berries per hour while picking.

If we were able to make production decisions that were efficient from the perspective of both groups combined, what would we consider to be the opportunity cost of producing one gallon of water?

3 berries

4 berries

25 cents

33⅓ cents