Which of the following statement is true?a) Molarity is the no. of moles of solute dissolved per litre of solventb) The molarity and normality of a solution of sodium carbonate are samec) Molality (m) of a solution is defined as the number of moles of solute dissolved is 1000 gm of solutiond) The ratio of mole fraction of solute and solvent is in the ratio of their respective moles.