Empirical formula of a compound is the formula showing the simplest whole number ratio of the atoms of elements present in the compound. It is the actual representation of whole number ratio between the elements in the compound. In this case, C2N2H8 is not an empirical formula simply because the ratio of the elements (2:2:8) is not the simplest ratio and could still be simplified further to a simpler ratio (1:1:4). Hence, the correct answer is A