Which of the following is true

A

The product of the eigenvalues of a matrix is equal to the trace of the matrix

B

The eigenvalues of a skew-symmetric matrix are real

C

A is a nonzero column matrix and B is a nonzero row matrix, then rank of AB is one

D

A system of linear non-homogeneousequationsis consistentif and only if the rank of the coefficient matrix is less than or equalto the rank of the augmented matrix