The formula weight of an acid is 82.0.$100cm^3$ of a solution of this acid containing 39.0g of the acid per litre were completely neutralized by $95.0cm^3$ of aqueous NaOH containing 40.0g of NaOH per litre.What is the basicity of the acid?

Question

$(a)\;1\qquad(b)\;4\qquad(c)\;3\qquad(d)\;2$