A square matrix B is skew-symmetric if A. BT = -B B. BT = B C. B-1 = B D. B-1 = BT

The correct answer is A. $BT = -B$.

A skew-symmetric matrix is a square matrix $B$ such that $BT = -B$. In other words, the transpose of a skew-symmetric matrix is its negative.

Option B is not correct because the transpose of a symmetric matrix is itself.

Option C is not correct because the inverse of a skew-symmetric matrix is not necessarily skew-symmetric.

Option D is not correct because the transpose of the inverse of a matrix is the inverse of the transpose of the matrix.