The Demand for Shoes in a Country Is Given by D

The demand for shoes in a country is given by D = 60 - 0.5P,where P is the price of a pair of shoes.Supply by domestic producers is given by S = 20 + 0.5P.The world price of a pair of shoes equals $30 and this economy is open to trade.If a tariff of $4 per pair is placed on shoe imports,the quantity of shoes produced domestically will change from ________ pairs with no tariff to ________ pairs with the tariff.

A) 35;40
B) 35;37
C) 40;35
D) 40;37
E) 37;40