If A=abb2−a2−ab then A is
Idempotent
Involutory
Nilpotent
Scalar
A=abb2−a2−ab A2=abb2−a2−ababb2−a2−ab =a2b2-a2b2a b3-a b3-a3b +a3b -a2b2+a2b2=0000