In which of the little scripts bellow, variable S holds a skew symmetric matrix. Remember a skew symmetric matrix is one whose transpose is the opposite (negative) of the matrix. Use matlab to confirm.

To confirm compute this variable S and check if the norm of the sum of S and its transpose is a very small number, that is norm(S+S'). If it is it is skew symmetric this norm should be a tiny number.

a.

A = rand(20,20); S =A*A-A'*A';

b.

A = rand(20,20); S =A*A+A'*A';

c.

A = rand(20,20); S =A*A^-1;

d.

A = rand(20,20); S =A*A';

e.

A = rand(20,20); S =(eye(20)+A)*(eye(20)-A)';

Clear my choice