Asolution contains 85.0 g of nano3, and has a volume of 750. ml. find the molarity of the solution

Molarity is defined as the number of moles in 1 L of solution.
Mass of NaNO₃ present - 85.0 g 
Molar mass of NaNO₃ - 85 g/mol
The number of NaNO₃ moles - 85.0 g / 85 g/mol = 1 mol 
Volume of solution - 750 mL
The number of moles in 0.750 mL - 1 mol
Therefore in 1 L solution, number of NaNO₃ moles - 1/0.75 = 1.33 mol
Therefore molarity of solution - 1.33 M

The correct answer is b

You use the atomic number to find out how many protons and neutrons there are in the atom. you use the atomic mass to find out how many protons and electrons there are in the atom.