Columnist: Over the last 20 years the demand in North America for Japanese-made automobiles has increased, whereas the Japanese demand for North American-made automobiles has been stagnant. Until recently, this imbalance could plausibly be attributed to Japanese models' superior fuel efficiency and reliability, but now cars made in North America are by these standards the equal of any Japanese model. What North American exporters continue to ignore is that the Japanese drive on the left side of the road. Ttherefore, one obstacle to reducing the automotive trade imbalance will be removed if North American manufacturers simply produce more cars with right-side steering wheels. Which one of the following is an assumption required by the columnist's argument? ['If the Japanese drive on the left side of the road, then they are not inclined to buy cars with left-side steering wheels.', 'Given a choice between similar Japanese and North American models, all with right-side steering wheels, most Japanese would choose the North American model.', 'Japanese automotive safety standards require that all new domestic automobiles have rightside steering wheels.', 'The automotive trade imbalance can be lessened only if North American manufacturers produce automobiles that more effectively meet the needs of Japanese buyers.']