A television manufacturing plant has a total of 1,000 workers, though

In this passage, the author concludes that "it is reasonable to assume that the plant could fire 10 workers without any loss in production." To support this conclusion, they point out that "on days when exactly 10 workers are absent, the plant produces televisions at its normal rate."

Let's consider the answers. The correct one should give us the grounds on which the "argument is most vulnerable to criticism."

The author concludes that the plant "could fire 10 workers without any loss in production." So even if the remaining workers produced "more televisions than previously," this would not weaken the argument, since this would not be a loss in production. (A) is incorrect.

The author supports the conclusion by stating that when 10 workers are absent, the plant produces televisions at its normal rate. So the argument hinges on the assumption that if 10 people were fired, then 10 people would be absent. But is this a reasonable assumption?

Earlier, the passage tells us that an average of 10 workers are absent on any given day. So if 10 people were fired, and the absentee rate stayed the same, the plant would have 20 fewer workers than usual. And if that were the case, it seems likely that production would fall, and the conclusion would be wrong. So for the argument to hold, we'd need to assume that if 10 people were fired, the absentee rate would drop. Because if it didn't, the number of workers would drop, causing production to drop.

So the fact that the argument "fails to show that the absentee rate would drop if 10 workers were fired" is strong grounds for criticism, and (B) is correct.

If anything, the argument seems to be taking it for granted that the normal rate of production can be attained even if MORE than the average number of works are absent. In other words, the argument seems to be assuming that if more than 10 workers were absent, production would stay the same. But it's certainly not assuming that the normal production rate can only be attained if NO MORE than 10 workers are absent, so (C) is out.

Notice the passage doesn't claim that the plant could fire ANY 10 workers, but just that the "plant could fire 10 workers without any loss in production." So even if there were some workers who were crucial to the production of televisions, this wouldn't harm the argument. As long as there are some workers at the plant who are NOT crucial, the conclusion holds up. And since we already know that production continues at the normal rate when an average of 10 people are absent, (D) is out.

The author claims that if 10 workers were fired, the plant could continue without any loss in production. For this argument to hold, the author doesn't need to assume that "the rate of production is not affected by the number of workers employed at the plant." Maybe the number workers employed at the plant does affect the rate of production? Maybe if 10 workers were fired, production would increase? Or maybe if say 50 workers were fired, it would affect the rate of production somehow? Any of these could be true, and the argument would still hold.

Since the author doesn't need to take it for granted that production is unaffected by "the number of workers employed at the plant," (E) is incorrect and we're left with (A).

I hope that helps!