Let \(A = \left( {\begin{array}{*{20}{c}} 0&0&{ - 1}\\ 0&{ - 1}&0\\ { - 1}&0&0 \end{array}} \right).\) The only correct statement about the matrix A is

• A. A is a zero matrix
• B. A2 = I
• C. A-1 does not exist
• D. A = (-1)I, where I is a unit matrix