Which would be inappropriate in a piece of research writing with a formal tone?

"and these i address to all females that would be married, or are already so; not that i suppose their sex more faulty than the other, and most to want advice, for i assure [women], upon my honour, i believe the quite contrary; but the reason is, because i esteem them better disposed to receive and practice it, and therefore am willing to begin, where i may promise myself the best success." this statement from franklin's "rules and maxims for promoting matrimonial happiness" best demonstrates his use of criticism to argue his point his use of common sense to appeal to women his use of flattery to gain women's attention his use of facts to prove his point