In Economics, What is Signalling?

Someone knows the answer i need in the exam

Your parents have accumulated a $170,000 nest egg. they have been planning to use this money to pay college costs to be incurred by you and your sister, courtney. however, courtney has decided to forgo college and start a nail salon. your parents are giving courtney $20,000 to her get started, and they have decided to take year-end vacations costing $8,000 per year for the next four years. use 8 percent as the appropriate interest rate throughout this problem. use appendix a and appendix d for an approximate answer, but calculate your final answer using the formula and financial calculator methods. a. how much money will your parents have at the end of four years to you with graduate school, which you will start then?

(a) what was the opportunity cost of non-gm food for many buyers before 2008? (b) why did they prefer the alternative? (c) what was the opportunity cost in 2008? (d) why did it change?