Objective: How can I create my own potting soil mix?

Which of the following solutions is more sound in terms of naive physics reasoning?

Select from the following.
(A). To make your own potting soil, mix 3 parts old soil, 1 part vermiculite, 1 part ring worm compost and a few scoops of fertilizer.
(B). To make your own potting soil, mix 3 parts old soil, 1 part vermiculite, 1 part worm compost and a few scoops of fertilizer.
(B).