The argument isn't based on a sample. The author doesn't, for example, cite to studies of people who eat sausages to reach a conclusion about the effects of sodium nitrate. We're not given any description of the basis for the statements about the effects of sodium nitrate and consumption of sodium, so we have no reason to think those statements are based on some kind of sample.

(If you're interpreting "insufficient sample" as though it refers to the idea that we don't know about all of the potential costs/benefits of sodium nitrate in sausages, you're understanding "sample" incorrectly. Citing to costs/benefits doesn't involve relying on a sample. Arguing based on a sample involves reaching a conclusion about a group based on a subset of that group. That's not what happens in this argument.)

This is very tempting, because it does seem like the author overlooks potential risks of not using sodium nitrate in sausages. What if, for example, lack of sodium nitrate makes sausages tougher to chew and more difficult to swallow, increasing the risk of choking when eating sausages?

But one problem with (B) is that the author does address at least some possible risks associated with removing sodium nitrate. In particular, she points out that sodium nitrate doesn't help prevent meat spoilage, which establishes that eliminating sodium nitrate won't increase the risk of spoilage. In other words, one of her premises shows that one possible risk of not using sodium nitrate (increased risk of spoilage) doesn't exist. This counts as "addressing" a possible risk. She might not address all potential risks, but it's inaccurate to claim that she "does not address possible risks."

It's not clear that the author's argument is directed toward what the government should do. Perhaps the author is simply telling sausage-makers not to add sodium nitrate. In addition, we have no reason to think that the public hasn't given their consent to the government or to whoever would have power to remove sodium nitrate from sausages. So the argument isn't making any assumptions about the government or consent.

This best describes a flaw in the argument. There are more moderate alternatives to the author's solution of eliminating sodium nitrate. In particular, why not just use a tiny, non-excessive amount of it? Or even a medium amount of it, but still underneath what's considered excessive? But the argument doesn't give us enough reason to rule out these alternatives. None of the premises indicate that a non-excessive amount would present any health risks to sausage-eaters. Although the author's line of reasoning might support the conclusion that we should make sure not to use an excessive amount of sodium nitrate in sausages, it doesn't prove that we should eliminate its use entirely in sausages.

There's no reason the author has to distinguish between medical and economic justifications to make her argument. So although the author doesn't make this distinction, this isn't why the argument is flawed.

If you like (E), you might be thinking that one weakness in the author's argument is that it's overlooking potential economic reasons for adding sodium nitrate to sausages (maybe it can somehow keep the costs of sausages down for the manufacturer or consumer). That is a weakness in the argument. But the way to describe that weakness is not what (E) says. The way to describe that weakness is "the argument fails to rule out the possibility that economic benefits of sodium nitrate outweigh the health-related reasons for eliminating sodium nitrate."