In Tim\textquotesingle s class, there are $$20$$ students who can swim, $$25$$ students who can play basketball, and $$10$$ students who can do both. If everyone in the class plays at least one sport, how many students are there in Tim\textquotesingle s class?~\uline{~~~~~~~~~~}~. 
选项为:A:$$25$$  B:$$35$$  C:$$45$$  D:$$55$$  请回答其中一个选项.