Identify the incorrect statements about group \( 15 \) elements :
(A) Dinitrogen is a diatomic gas which acts like an inert gas at room temperature.
(B) The common oxidation states of these elements are \( -3, +3 \) and \( +5 \).
(C) Nitrogen has unique ability to form \( p\pi - p\pi \) multiple bonds.
(D) The stability of \( +5 \) oxidation states increases down the group.
(E) Nitrogen shows a maximum covalency of \( 6 \).