The most accurate response is:
Consumers in both countries will benefit. Oil producers in Canada and auto part manufacturers in the U.S. will benefit. Oil producers in the U.S. and auto part manufacturers in Canada will be at a disadvantage.
This response reflects the idea that trade allows for specialization and efficiency, leading to lower prices and greater selection for consumers. However, it also suggests that there will be sectors that may suffer due to increased competition and shifts in market dynamics, specifically those in the U.S. oil production and Canadian auto parts manufacturing sectors.