Answer :
The answer is C. Use conversion rates to change one unit into the other unit, so that both prices are listed using like units.
You can't compare the two until they are the same units, so the other options don't work.
You can't compare the two until they are the same units, so the other options don't work.
The correct answer is option C. "Use conversion rates to change one unit into the other unit, so that both prices are listed using like units". Conversion rates are a useful way to equalize the unit price of two comparable items. For instance, a conversion rate could be applied by expressing the prices in percentages by dividing the total cost of the product against the units at which the product could be divided (weight or volume).