Who pays a corporate income tax?

There was an extensive black market (illegal market) for many consumer products in the United States during World War II. A likely explanation of the black market is that:

a. the prices of goods were artificially held down by price controls. b. black markets were legal during the war. c. goods were not subject to price controls. d. gasoline rationing greatly restricted civilians from driving to stores.

Why do governments often intervene in international trade to restrict imports and expand exports?

What will be an ideal response?