When the volume is expressed,what does the law of definite proportions represent?

One part of an element $A$ combines with two parts of another element $B$. Six parts of the element $C$ combine with four parts of the element $B$. If $A$ and $C$ combine together,the ratio of their weights will be governed by

Statement $1$: Creation or destruction of atoms is not possible.
Statement $2$: Under identical conditions of temperature and pressure,the number of atoms/molecules in a given volume of gas is not the same.

"Mass can neither be created nor destroyed" is the statement of

Among the following pairs of compounds,the one that illustrates the law of multiple proportions is

When $3 \ g$ of a hydrocarbon is burnt in the presence of sufficient oxygen,it produces $8.8 \ g$ of $CO_2$ and $5.4 \ g$ of $H_2O$. This process is an example of which law?