Essentials of Economics 7th Edition by Gregory Mankiw

Exercise 9

When a nation opens itself to trade in a good and becomes an importer,
A) producer surplus decreases, but consumer surplus and total surplus both increase.
B) producer surplus decreases, consumer surplus increases, and so the impact on total surplus is ambiguous.
C) producer surplus and total surplus increase, but consumer surplus decreases.
D) producer surplus, consumer surplus, and total surplus all increase.