(E) says, "The main category of risk that is usually incurred completely involuntarily is the risk of natural disaster."
The problem with (E) is that the passage doesn't say anything about the main category of involuntary risk. The passage only mentions asteroid risks, but it's entirely possible that there could be other types of involuntary risks as well, so we don't have enough material to support (E), as the author never provides us with any sort of comprehensive list of which risks are considered to be totally involuntary.
(B) says, "The fact that plane crash victims chose to fly would usually be deemed by policy experts to be largely irrelevant to decisions about the government’s role in regulating air safety."
(B) looks great, and there's textual support for it in lines 9 through 13. The voluntariness of a risk is a key difference between how laypeople and experts judge risks. The experts focus on aggregate lives at stake, whereas regular folks care about whether or not an activity was voluntary. Thus, the author would definitely agree with (B), as it summarizes precisely how experts would view that situation (they wouldn't care about whether or not plane victims chose to fly; they'd be focusing on aggregate lives at stake).
Does this make sense? Let us know if you have any other questions!