Helpppp. I don’t understand what I’m supposed to do

-15

Explanation:

That's the answer because the missing number is -15 just look at it carefully.

B. -5

Explanation:

-5 cant equal 20, because it already shows on the table that it equals 15.  

B) The increase in demand made the South the center of the U.S. economy and the North was dependent on southern production