D - This is not a redox reaction because no electrons were transferred.
In Redox reactions, typically subscripts are replaced with a coefficient. In the equation given, each reactant and product maintains the same subscripts that they began with and did not gain a coefficient, thus, not being a redox reduction.
The type of bonds present in the compound. and the type of structure it has and the elements that are presents and the number of moles of each element in one mole of the compound.