Let `Aa n dB` be two nonsingular square matrices, `A^T a n dB^T` are the transpose matrices of `Aa n dB ,` respectively, then which of the following options are correct? (correct option may be more than one) `(a)`. `B^T A B` is symmetric matrix `(b)`. if `A` is symmetric `B^T A B` is symmetric matrix `(c)`. if `B` is symmetric `B^T A B` is skew-symmetric matrix for every matrix `A` `(d)`.`B^T A B` is skew-symmetric matrix if `A` is skew-symmetric