Which of the following is not a period cost?

A period cost is Rent because the amount does not change with a change in production and it is an amount that is charged whether you produce anything.

A non period cost will be labor or materials because the amount will change as your production changes. If you produce one product you use 1 set of materials, but if you produce 2 prodcuts you will use 2 sets of materials so the amount changes as your production incrfeases or decreases in an acocunting period.