The best approach would be to calculate the unit rate of each bag. The unit rate is the price of each unit, so if we find the bag which has the lower price per unit that is the one we should buy. In order to calculate the unit rate we need to divide the price of the bag by the number of apples it has. This is done below:
If we look at the unit rates we will notice that the price per apple from Red Delicious is the cheapest, therefore is the one we should buy.
The correct answer is the second option.