Moe has a big exam tomorrow. he considered studying this evening, but decided to go out with curly instead. since moe always chooses rationally, it must be true that:
a. the opportunity cost of studying tonight is less than the value moe gets from spending time with curly.
b. the opportunity cost of studying tonight is equal to the value moe gets from spending time with curly minus the cost of earning a low grade on the exam.
c. moe gets more benefit from spending time with curly than from studying.
d. moe gets less benefit from spending time with curly than from studying.

Astudent was asked to draw a demand and supply graph to illustrate the effect on the market for premium bottled water of a fall in the price of electrolyteselectrolytes used in some brands of premium bottled​ water, holding everything else constant. she drew the graph to the right and explained it as​ follows: ​"electrolyteselectrolytes are an input to some brands of premium bottled​ water, so a fall in the price of electrolyteselectrolytes will cause the supply curve for premium bottled water to shift to the right​ (from upper s 1s1 to upper s 2 right parenthesis .s2). because this shift in the supply curve results in a lower price left parenthesis upper p 2 right parenthesis commap2, consumers will want to buy more premium bottled water and the demand curve will shift to the right​ (from upper d 1d1 to upper d 2 right parenthesis .d2). we know that more premium bottled water will be​ sold, but we​ can't be sure whether the price of premium bottled water will rise or fall. that depends on whether the supply curve or the demand curve has shifted farther to the right. i assume that the effect on supply is greater than the effect on​ demand, so i show the final equilibrium price left parenthesis upper p 3 right parenthesisp3 as being lower than the initial equilibrium price left parenthesis upper p 1 right parenthesis .p1.​" where is the flaw in the​ student's argument? supply will shift inward. demand will not shift. demand will shift inward.