In the long run, all of a firm's inputs are variable

The Ricardian model of comparative advantage lends support to the argument that

A) trade tends to worsen the conditions of unskilled labor in rich countries. B) trade tends to worsen the conditions of owners of capital in rich countries. C) trade tends to worsen the conditions of workers in poor countries. D) trade tends to worsen the conditions of workers in rich countries. E) trade is mutually beneficial to the countries that engage in it.

Suppose that each worker must use only one shovel to dig a trench, and shovels are useless by themselves. In the long run, the firm's cost function is

A) TC = (w/r) ? q. B) TC = (w + r)/q. C) TC = (w + r). D) TC = (w + r) ? q.