The diagram below shows supply and demand curves for comic books in the domestic Canadian market.

FIGURE 20-5
Refer to Figure 20-5. The world price is $3 per comic book. Canada engages in free international trade then imposes a $2 tariff on comic books. With this change, the foreign producers' revenue ________ per month.
◦ decreases by $1 080 000
◦ increases by $2 940 000
◦ increases by $960 000
◦ increases by $1 980 000
◦ decreases by $2 400 000