Im pretty sure it would be d.
Well, something that I noticed is that the left side is equal to the right side meaning that the sum of the right side is equal to the sun of the left side.
Here are the CORRECT names and molecular formulas
carbonate:

bicarbonate:

Choice 1 is incorrect
nitrite:

nitrate:

Choice 2 is incorrect
sulfite:

sulfide:

Choice 3 is incorrect
By process of elimination, you can infer choice 4 is correct.
Actually, choice 4 is the only choice that displays the correct name and formula.
Have an awesome day! :)
A.
The first energy level has 2 electrons, the second has 8, and the third has 4
The correct answer is carbon.
The element carbon is found in all the organic constituents in the body of a human that comprises carbohydrates, fats, proteins, and nucleic acids. It is the second most abundant element found in the body of a human being. In supplementation to being a basic building block of the majority of the cellular compositions of the body, carbon is found in the blood as carbonic acid and bicarbonates.