If A=(1000)A = \begin{pmatrix} 1 & 0 \\ 0 & 0 \end{pmatrix}A=(1000), which of the following is true?
A2=AA^2 = AA2=A
A2=0A^2 = 0A2=0
A2=IA^2 = IA2=I
AAA is invertible