Which of the following does not show the law of conservation of mass?

a. 24 g of mg burn in 32 g o2 to produce 56 g of mgo.

b. 24 ml of mg burn in 32 ml o2 to produce 56 ml of mgo.

c. 2 atoms of mg react with 1 molecule of o2 to produce 2 units of mgo.

d. 1 atom of mg reacts with 1 atom of o to produce a unit of mgo that contains 2 atoms.