Students don't tend to have a lot of money available and a good way to save if you attend college out of state and are traveling home is to check web sites to find out about discounts available for students. This, as many companies offer these types of discounts to target students as it is known they are sensitive to prices and also, they can become an important market to get for the future.
I would select A. Nitrogen due to the fact Nitrogen is found in most soil samples and Aluminum and mercury are metals. Also, limestone i don't find beneficial to plants whatsoever.
