Both bc your buying the product and a service of them installing it
By use IUPAC nomenclature rule compound N2O3 is named as
Dinitrogen trioxide ( answer d)
Nitrogen (N2) is named before oxygen(O3) since they are arranged alphabetically. In addition the prefix Di is used infront of nitrogen since they are two nitrogen atoms while prefix tri is used infront of oxide since they are 3 oxygen atoms
Veins is the correct answer