An airline's plane from los angeles to new york is about to take off, but it still has a few seats empty. if the average cost per seat is $500, what price should the airline charge passengers in standby to fill in those remaining seats? (consider that quantitative decisions are made at the margin) select one: a. at least $500. b. exactly $500. c. any price above zero that will entice standby passengers to take the flight. d. slightly less than $500.