Using a diagram and the concept of “producer surplus" and “consumer surplus”, explain: A) How international trade could increases economic welfare, when the world price of a tradable good is...

Using a diagram and the concept of “producer surplus" and “consumer surplus”,
explain: A) How international trade could increases economic welfare, when the world
price of a tradable good is lower than the domestic price ‘
B) How protective import tari?’s would affect economic welfare of this economy