Which one of the following is a false statement?

III  . . . meso tartaric acidI and II are dextro and laevo isomersI & III   .   .   .   diastereomersII & III   .   .   .  diastereomers;n-propyl alcohol and isopropyl alcohol are positional isomers. They differ in the position of functional group but have the same IUPAC root word ;