A thirteenth-century book purporting to record an account given by Marco Polo, a Venetian merchant, of a journey he supposedly made to China contains no description of the Great Wall of China. Marco Polo would have had to cross the Great Wall to travel the route described and, obviously, would not have omitted mention of the Great Wall if he had seen it. Most probably, therefore, Marco Polo never did actually travel to China.The conclusion of the argument is the following:
Most probably ... Marco Polo never did actually travel to China.The support for the conclusion is the following:
A thirteenth-century book purporting to record an account given by Marco Polo, a Venetian merchant, of a journey he supposedly made to China contains no description of the Great Wall of China. Marco Polo would have had to cross the Great Wall to travel the route described and, obviously, would not have omitted mention of the Great Wall if he had seen it.We see that the author has reasoned that, since Marco Polo would have mentioned the Great Wall if he had seen it, since he would have had to cross it to travel the route described in the book, and since the book does not mention the Great Wall, it's probable that Marco Polo didn't actually travel to China.
The argument relies on which of the following as an assumption?The correct answer will state something that the argument relies on, in other words, something that has to be true for the argument to work.
A) The route described is the most direct one that Marco Polo could have taken.The argument does not rely on this being true.
After all, regardless of whether the route described is the most direct route, it is supposedly the one Marco Polo took.
So, the argument works even if this choice is not true.
Eliminate.
B) Marco Polo had no communication with any traveler who had seen the Great Wall.This choice could follow from what the passage says. After all, if Marco Polo did not mention the Great Wall, then it seems likely that he didn't talk with anyone who had seen it.
At the same time, we don't need a choice that follows from what the passage says. We need an assumption on which the argument relies, and the evidence supports the conclusion that, most probably, Marco Polo never did actually travel to China regardless of whether he had any communication with someone who had seen the Great Wall.
After all, regardless of whether he had such communication, he didn't mention the Great Wall. So, it seems unlikely that he traveled to China.
Eliminate.
C) The book's author most probably included in the book only information obtained from Marco Polo firsthand.This choice is tricky because we might think that this choice has to be true for the argument to work since the point of the argument is that the author didn't mention the Great Wall because Marco Polo didn't mention it. So, the reasoning of the argument involves the idea that the book's author was getting information from Marco Polo firsthand.
At the same time, this choice doesn't have to be true for the argument to work. After all, even if the author included in the book information from sources other than Marco Polo, the author still didn't mention the Great Wall. So, it still seems likely that Marco Polo didn't mention and, therefore, must not have seen the Great Wall.
Eliminate.
D) It is unlikely that the book's author suppressed as blatant fabrication any references Marco Polo might have made to the Great Wall.Let's negate this choice and see what happens to the argument if it's not true. Negated, this choice is the following:
It is LIKELY that the book's author suppressed as blatant fabrication any references Marco Polo might have made to the Great Wall.Notice that if it's likely that the book's author suppressed any references Marco Polo might have made to the Great Wall, then the argument falls apart. After all, in that case, it could be that Marco Polo traveled to China, saw the great wall, and mentioned the Great Wall to the author of the book, but the author decided not to mention it.
In other words, in that case, we have an alternative explanation for the book's not mentioning the Great Wall. Rather than the explanation being that Marco Polo didn't travel to China, the explanation could be that the author thought Marco Polo's references to the Great Wall were "fabrication," i.e., made up, and therefore didn't include those references to the Great Wall in the book.
So, the argument doesn't work of this choice is not true, and thus works only if this choice is true.
Keep.
E) If Marco Polo had seen the Great Wall, he would have considered it the most notable structure in China.This choice is tempting because the argument does involve the assumption that Marco Polo would have considered the Great Wall "notable," in other words, worth mentioning.
At the same time, this choice goes too far because the argument works even if Marco Polo did not consider the Great Wall "the
most notable."
After all, as long as he considered it notable, he would likely have mentioned it, even if it were not the
most notable.
Eliminate.
Correct answer: D