A 5.25% solution of a substance is isotonic with a 1.5% solution of urea (molar mass = 60g mol–1) in the same solvent. If the densities of both the solutions are assumed to be equal to 1.0gcm–3, molar mass of the substance will be
(a) 210.0g mol–1
(b) 90.0g mol–1
(c) 115.0g mol–1
(d) 105.0g mol–1 .
