Let \( A \) and \( B \) be any two \( 3\times 3 \) symmetric and skew symmetric matrices respectively. Then which of the following is NOT true?
\( A^{4}-B^{4} \) is a symmetric matrix
\( AB-BA \) is a symmetric matrix
\( B^{5}-A^{5} \) is a skew-symmetric matrix
\( AB+BA \) is a skew-symmetric matrix