Which of these can be classified as a pure substance a. solution b. heterogeneous mixture c. compound d. homogeneous mixture

C. Compound, a pure substance is a compound.

Compound is the  pure substance

   Explanation

A compound is a pure substance which is made up of two or  more differences atoms which are chemically bonded to one another.compound cannot be physically separated.On other side  if the substance is not  chemically  pure it is referred to as heterogeneous or homogeneous mixture.  solution is an example of  a mixture therefore it no t pure.

The molar mass of a substance is defined as the mass of 1 mol of that substance, expressed in grams per mole, and is equal to the mass of 6.022 × 10 23 atoms, molecules, or formula units of that substance.