What Was Samuelson's Criticism of Free Trade

What was Samuelson's criticism of free trade?

A) He argued that dynamic gains lead to a universally beneficial outcome for all countries.
B) He argued that offshoring service jobs that were traditionally mobile will increase the market clearing wage rate.
C) He argued that free trade has historically been beneficial only to third world countries.
D) A rich country importing cheap goods from a poor country may not make up for the wage losses in the rich country.