The symmetric difference of A and B is

(a) $\displaystyle (A-B) \cap (B-A)$

(b) $\displaystyle (A-B)\cup (B-A)$

(c) $\displaystyle (A \cup B) - (A \cap B)$

(d) $\displaystyle \{(A \cup B)-A\} \cup \{(A \cup B)-B\}$

Its answer given in the book is (b). But I found that (c) and (d) are also true. Am I right? If not please tell why. Thanks a lot for giving me your time.