The situation you described involves Canada reducing the quantity of steel it exports to Japan, which would generally lead to an increase in the price of steel due to a smaller supply in the Japanese market. Among the options provided, the action that would have a similar effect on the quantity imported and the price paid for Canadian steel by Japanese producers would be:
Japan implements an import quota on Canadian steel.
An import quota would directly limit the quantity of Canadian steel that can be imported by Japan, similar to Canada's voluntary reduction in exports. This restriction would likely lead to a higher price for the limited quantity of Canadian steel available in Japan, aligning with the intent to reduce exports from Canada.