A 4-pound bag of grass seed costs $20. A 12-pound bag of grass seed costs $36.

How much less does each pound of grass seed cost if a customer buys a 12-pound bag?

A.
The costs for each pound are the same.

B.
The cost for each pound is $1 less.

C.
The cost for each pound is $2 less.

D.
The cost for each pound is $3 less.
please answer this quickly