38.在 C 語言中,設有變數宣告 int a = 6, b = 12;,若執行敘述 a += b++;,則執行完畢後 a 與 b 的值 分別為何?(A) a = 18, b = 12(B)a = 18, b = 13(C) a = 19, b = 13(D) a = 6, b = 13