You might be drawn to (A) because it mentions something that "sometimes accompanies" unsafe smog, which sounds like the east wind. But the author doesn't think that the east wind necessarily accompanies unsafe smog. The conclusion just says that on some east wind days, the smog reaches unsafe levels.

It's possible you think the condition that "sometimes accompanies" unsafe levels of smog is hot days. But even then, the author doesn't assume that hot days necessarily accompany unsafe smog levels.

This accurately describes the flaw using the language of sets. The "one set" is hot days. The "two others" (meaning two other sets) are unsafe smog days and east wind days. Hot days has members in common with each of those two sets (some hot days have unsafe smog, and some hot days have east wind). But the argument fails to recognize that unsafe smog days and east wind days might have no members in common with each other, as illustrated in the second diagram above.

"Unsafe" means the same thing in both the premise and the conclusion: the smog has reached a level that isn't safe. There's no shift in meaning.

This describes circular reasoning. But the premises aren't circular. We can accept that some hot days have unsafe smog and that some hot days have east wind without already believing the conclusion. These premises describe separate observations that don't depend on the conclusion being true.

You might be drawn to (E) because the argument involves two things (east wind and unsafe smog) that coincide with a third thing (hot days), which can look like a correlation. But the argument doesn't claim that east wind causes unsafe smog or that unsafe smog causes east wind. The conclusion is just that both happen on the same day sometimes.