Which of these would have been most likely to be regulated by the w. i. b. during world war i? farming steel mills free speech minority hiring?

The correct answer is steel mills

The W. I. B. was the war industries board and they would care about steel mills because steel mills would produce steel weaponry for their troops during world war one. They didn't care much about farming or minority hiring, and especially not about free speech since they introduced the espionage act which basically meant that free speech didn't exist if you spoke against the war.