Jack estimates that the cost per mile, in dollars, for operating a certain truck is between 15% and 21% of the number of miles driven. this is shown by the system of inequalities below, where x represents the number of miles driven and y represents the cost of operating the truck. y ≥ 0.15x y ≤ 0.21x based on this information, which statement is true? a) if jack drives over 15 miles, it will cost 15 · 0.15 to operate the truck. b) if jack drives less than 21 miles, it will cost 21 · 0.21 to operate the truck. c) if jack drives the truck 100 miles, it will cost either $15 or $21. d) if jack drives 200 miles, it will cost anywhere between $30 and $42.