Unripe lychee fruit contain a compound called hypoglycin, which is poi

Yeah, only the GMAT could take something as tasty as lychee fruit and turn it into a not-so-delicious CR question...

The conclusion of this passage is that "unripe lychee-B fruits are at least as safe to eat as ripened, conventional lychees of the same size." Let's see how the author arrived at that conclusion.

The first two sentences are pretty straightforward:

• Unripe lychee fruit contain a compound called hypoglycin.
• Hypoglycin is poisonous in large quantities. In fact, eating unripe lychee fruit can apparently lead to death.
• No amount of ripe lychee fruit contains enough hypoglycin to harm human health.

So far we can gather that eating unripe lychee fruit might harm your health (or even kill you) if you eat enough of it, though we can't say exactly how much would be unsafe. On the other hand, you can eat as much RIPE lychee fruit as you want and not be harmed by the hypoglycin. Note that this does not necessarily mean that you can eat as much lychee fruit as you want without suffering other negative consequences. All we know for sure is that doing so would not expose you to harm from the hypoglycin.

In response to recent deaths of consumers who ate unripe lychee fruit, scientists developed lychee-B, which, ripe or unripe, contains no more hypoglycin than ripened, conventional lychees. Since lychee-B contains no more hypoglycin than ripened, conventional lychees, we can conclude that you could eat as much ripe OR unripe lychee-B as you want without being harmed by the hypoglycin. As with ripened, conventional lychees, that doesn't mean that you won't suffer OTHER negative consequences from eating lychee-B all day long, but you certainly won't be harmed by the hypoglycin.

Based on this information, the author of the passage concludes that: "unripe lychee-B fruits are at least as safe to eat as ripened, conventional lychees of the same size." In order for that conclusion to be properly drawn, which of the following must be assumed?


Without this assumption, it is possible that unripe lychee-B fruits contain more arsenic, oxalic acid, or other poisonous substances than do ripened, conventional lychees. The information in the passage tells us that if we only consider hypoglycin, lychee-B fruits are at least as safe to eat as ripened, conventional lychees of the same size. But if lychee-B contains higher quantities of OTHER poisonous substances besides hypoglycin, then lychee-B might be less safe overall than conventional, ripened lychees. Thus, choice (A) looks like a required assumption, so hang on to it.


The conclusion specifically tells us that we are comparing lychee-B fruits to conventional lychees OF THE SAME SIZE. So even if lychee-B fruits are bigger on average, this would not impact the conclusion. Choice (B) can be eliminated.


The conclusion compares UNRIPE lychee-B to RIPENED conventional fruits. It makes no difference how much hypoglycin was in the ripened conventional fruit prior to ripening OR how much hypoglycin is lost by a lychee-B during the ripening process. Since we are told that lychee-B, ripe or unripe, contains no more hypoglycin than ripened, conventional lychees, the conclusion is possible, with or without this assumption. Eliminate (C).


As stated above, it is possible that eating a large number of conventional lychee fruits OR a large number of lychee-B fruits is harmful to human health. Choice (D) does not tell us WHICH type is more harmful or how much of each would have to be eaten to cause harmful effects. Thus, it is still possible that unripe lychee-B fruits are at least as safe to eat as ripened, conventional lychees of the same size. Eliminate (D).


The conclusion of the passage has nothing to do with whether consumers would actually be willing to eat unripe lychee-B fruits. The conclusion simply states that unripe lychee-B fruits are at least as safe to eat as ripened, conventional lychees of the same size. Even if lychee-B fruits were completely tasteless and nobody wants to eat them, the conclusion of the passage would not be impacted. Eliminate (E).

Choice (A) is the best answer.