Acid and Base the 4th option because, on the pH scale the acid and base meet at the middle and become neutral.
On addition to water the Na+ section of NaCl is attracted to the oxygen side of the water molecules, while the Cl- side is attracted to the hydrogen's side of the water molecule. This causes the sodium chloride to split in water, and the NaCl dissolves into separate Na+ and Cl- atoms.(Long story short one becomes positive the other negative)
When a non- metal and metal combine (to my knowledge) forms a metalloid.
I have no idea what ionic compounds are so like wrong answer(?) XD
The answer is acid and base
I hope I helped
P.S. I know you didn't read all of that don't say you did) XD