If a matrix A = [A11 A12 ⋯ A1n A21 A2n ⋮ ⋮ An1 An2 ⋯ Ann ], order(nxn) Aii = 1, Aij = 0 for i ≠ j. Then that matrix is know as

• A. Identity matrix
• B. Null matrix
• C. Singular matrix
• D. None of the mentioned