If~$A\textbackslash{} \blacksquare\textbackslash{} B=(A\times A)-B$, then~$(3\textbackslash{} \blacksquare 4)\textbackslash{} \blacksquare\textbackslash{} 5$~$=$ $$ 
选项为:A:$$0$$  B:$$6$$  C:$$20$$  D:$$35$$  请回答其中一个选项.