The correct one is Respiratory Distress !!
As rest are not concerned with air pollution !!
It is (CI) bromine
because, <span>Halogen element, any of the six nonmetallic elements that constitute Group 17 (Group VIIa) of the periodic table. The halogen elements are </span>fluorine (F)<span>, </span>chlorine (Cl), bromine (Br<span>), iodine (I), astatine (At), and tennessine (Ts).</span>
After the first 2 min the 20 g are only 10g, (1 half-life)
after other 2 more min 5g (2 half-lives)
after other 2 more min 2.5 g (3 half-lives)
after 2 more 1.25 g (4 haf lifes)
It would be one electron in the outermost shell. Hope this helps!
