Let A=(1101)A = \begin{pmatrix} 1 & 1 \\ 0 & 1 \end{pmatrix}A=(1011) and B=(2012)B = \begin{pmatrix} 2 & 0 \\ 1 & 2 \end{pmatrix}B=(2102). Which statement is true?
AB=BAAB = BAAB=BA
det(AB)=det(A)det(B)\det(AB) = \det(A)\det(B)det(AB)=det(A)det(B)
AAA is invertible and BBB is singular.
Both AAA and BBB have rank less than 2.