Answer:
(C) Oxygen because it has the strongest attractive force and the largest
electronegativity
Explanation:
Oxygen will be most reactive
configuration = 
As oxygen need only two electrons to complete its octet.
Oxygen will have stronger force than nitrogen as it will tend to pull electrons more to complete its octet. Also along the period electronegativity increases so oxygen has higher electronegativity than nitrogen
As,
Water has a pkw=14
so it can be represented as,
[H+] [OH-] = 1*10^-14
If [H+] = 3*10^-5M
[OH-] = (1*10^-14) / ( 3*10^-5)
[OH-] = 3.3*10^-9 M
Lead.
Lead paint was a big problem and now lead has been removed from paint because it was found to be dangerous to the health of living organisms.
Hope this helps! :)
Calcium has the least attraction for electrons in a chemical bond