Whenever we're asked to explain a situation or discrepancy like this, we first have to analyze the evidence given.

Building with bamboo rather than steel or concrete makes sense because... it's strong, sturdy, less expensive, and readily available.

EXCEPT where land values are high.

So why would the price of the land impact any of the qualities that make bamboo desirable? We need to find an answer choice that states that one of these desirable qualities is somehow affected by the value of the land. When you're looking through the answer choices, be wary of statements that undermine the evidence given in the argument (e.g. "bamboo is not as good as steel generally"), or statements that disprove the stated exception (e.g. "bamboo is always the best").

The right answer choice will introduce a new premise, so it's ok to pick something that seems irrelevant at first. You should expect new information - just ask whether it supports that exception, without undermining the given evidence.

(A) Don't eliminate this just because earthquakes seem irrelevant at first. If this answer had said instead "earthquakes only happen where land values are high, and steel and concrete are better than bamboo in earthquakes," it would have been right! The problem is that this doesn't make any comparison between high land values and other places.

(B) Multistory buildings... do they have anything to do with land value? It might not seem like it at first, but think - where and why are multistory buildings built? Where land is expensive (in cities), we build up rather than out. If bamboo can't be used for tall buildings, then it won't be used in places where land values are high. This explains why the one exception to the desirability of bamboo is "where land values are high." CORRECT!

(C) This seems to undermine the given premise that bamboo is less expensive than other building materials, but we know that the given premises must be true. And you're right, the termites don't have any connection to high land values.

(D) Are tropical areas connected to high land values? No. Does the fact that it's used for scaffolding affect whether it's used for the actual building? No - it's readily available, so there's plenty to go around.

(E) This one is tempting, because it actually addresses land values. But be careful! Is "where land values are increasing" the same as "where land values are high"? The value could be increasing from "really low" to "kind of low." And does the fact that we clear away the bamboo that's growing there mean that we can't also build with it? No.


Answer choice B requires a few jumps in logic, but it's the only choice that connects land value to bamboo's suitability.