Official Explanation
Argument Evaluation
To keep bread affordable in Suriland, the country's government requires that wheat farmers in the country sell their wheat to the government for one dollar per bushel less than the world market price.
This question requires us to identify a statement that seriously weakens the argument. The conclusion of the argument is that, if these wheat farmers could legally sell their wheat on the world market, they would make a dollar per bushel more, minus additional transportation and brokerage costs.
However, this argument assumes that the world market price for wheat is fixed and would not be affected by introducing Suriland's wheat supply. That is, it is possible that the world market price per bushel for wheat might decline as a result of an increase in the wheat supply available on that market. If this were the case, it would severely weaken the argument.
A. This choice is outside the scope of the argument: the argument is about Suriland's wheat farmers increasing how much money that can receive per bushel, not about how these farmers' costs compare to the costs of farmers in other countries. In any case, this claim does not indicate that Suriland's wheat farmers could make a dollar more, minus any additional transportation and brokerage costs, than they do now.
B. Correct. An increase in supply on the world market with no increased demand could easily depress the price of wheat on the market. It is still possible that Suriland's farmers would make more than they do now, even after subtracting additional transportation and brokerage costs. But the argument specifically says that the farmers would make a dollar more, minus those costs, and that does not follow if the claim made in this answer choice is true.
C. Note that the argument suggests that these farmers would make a dollar per bushel more, less any additional transportation and brokerage costs they would have to pay. That could still be true no matter what those costs are.
D. Whether Suriland's wheat is sold to near or distant countries is immaterial to the argument; note that the conclusion includes the qualification less any additional transportation costs.
E. This indicates that Suriland wheat farmers might sometimes lose money on their wheat if selling on the world market. This does not indicate, however, that they would not lose less on the world wheat market than they would selling to the government. Note that the government's price for wheat is pegged to the world market, so the price the world market offers and the price the government offers will always differ by the exact same amount: the government pays one dollar less.
The correct answer is B.