Which Statement Is Incorrect

Which statement is incorrect?

A) Ionic compounds generally contain metal and nonmetal elements.
B) Formulas of ionic compounds are written with the anion first, then the cation.
C) Cations and anions combine in the simplest ratio which achieves electrical neutrality.
D) The number of electrons lost by the cation(s) must equal the number gained by anion(s) in an ionic compound.