Wal-mart sells a case of 24 cans of Diet Coke for $6.88. Kroger sells a 12 pack of Diet Coke for $3.99. Determine the unit rate for both and which is the best buy? Round to the nearest cent.

Which statement is true about the extreme value of the given quadratic equation? a. the equation has a maximum value with a y-coordinate of -21. b. the equation has a maximum value with a y-coordinate of -27. c. the equation has a minimum value with a y-coordinate of -21. d. the equation has a minimum value with a y-coordinate of -27.