I believe the answer here is B.

First of all logical gap: premises talk about driving left and conclusion is about manufacturing right sided handle.

1) So the correct answer should have some relation between left side driving and right sided steering.

2) Also one important point to note here is that this is one of the obstacles so there can be other obstacles too. So an answer which says that this is only the solution can be neglected.

With point 2) as our basis of prethinking we eliminate E.

Based on above reasoning we can eliminate A and C as they talk about something that does not draw any link between left sided driving and right sided steering.

Left with B and D.

Assumption is an unstated premise

Let's consider option D. It says most. Even if we consider most to be (51%) we are still left with 49% who might want the car. So this option can act as a strengthener but it's not the must be true.

Negation of it gives us "not most" and we can see that this does not break the conclusion.

Option B hence is our answer.

Also negating B shatters the conclusion.

Posted from my mobile device

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. Therefore, one obstacle to reducing the automotive trade imbalance will be removed if North American manufacturers simply produce more cars with right-side steering wheels.

Boil it down - one obstacle to reducing the automotive trade imbalance will be removed if North American manufacturers simply produce more cars with right-side steering wheels.

Type- assumption

(A) The fuel efficiency and reliability of cars made in North America will continue to increase. - Irrelevant
(B) If the Japanese drive on the left side of the road, then they are not inclined to buy cars with left-side steering wheels. - Correct; Japanese would be inclined to buy cars with steering wheels on the left, and the argument wouldn't make sense!
(C) Japanese automotive safety standards require that all new domestic automobiles have right-side steering wheels.- incorrect
(D) Given a choice between similar Japanese and North American models, all with right-side steering wheels, most Japanese would choose the North American model. - incorrect - We don't need most Japanese to choose a North American car when faced with two choices that both have steering wheels on the right.
On negating option D, North American cars with steering wheels on the right WOULD NOT be more popular than Japanese cars, but perhaps they would sell well enough to see sales rise.
(E) The automotive trade imbalance can be lessened only if North American manufacturers produce automobiles that more effectively meet the needs of Japanese buyers. - incorrect; Perhaps which side the steering wheel is on is a stylistic issue, not a "need" issue. Furthermore, the "only" in this answer is problematic.

Answer B
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