If , then A^T + A = I₂, if

If A is 3 × 4 matrix and B is a matrix such that A^TB and BA^T are both defined. Then, B is of the type

If A = [a_ij] is a square matrix of even order such that a_ij = i² – j², then

If is expressed as the sum of a symmetric and skew-symmetric matrix, then the symmetric matrix is

Out of the following matrices, choose that matrix which is a scalar matrix: