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 demanded domestically will change from ________ pairs with trade,but no tariff,to ________ pairs with trade and a tariff.

A) 40;43
B) 40;45
C) 43;40
D) 45;40
E) 45;43