What are the relevant costs in this decision?

You have to decide between renting apartment C at a cost of $400 or an apartment D at a cost of $550. Because apartment D is larger the utility bill will be $125 per month rather than the $50 for apartment C. You need a parking space. It is included in the rent for Apartment C. If you rent apartment D, you will have to pay an additional $50 for parking. Your food bill is $250 and your cell phone costs you $100.