VC = Direct Materials Cost for a combo is (assuming lb. of fries and 1 soda in the combo) (ignore oil cost for frying)

Select one:

a. $3.75

b. $4.00

c. $4.50

($7/Burger + $2.00 for Soda and Fries; Break-even is $153 / ($9 - $4.50) = 34 burgers.)