My account on The Slap got deleted :(

Which of the following covers all qualified higher education expenses

Firms use marginal analysis to determine prices by a) changing prices in accordance with information from retailers. b) using comparisons with strong competitors to position prices accordingly. c) examining the effect on revenue of small changes to the price of one item. d) trying to minimize production costs by using better and more efficient methods.

Why does the blending of many different diciplines present both challenges and opportunities to enviromental scientist?