Mary\textquotesingle s violin class started at $$11.15\textbackslash{} \text{a .m.}$$ It lasted for $$90$$ minutes.  What time did her violin class end? 
选项为:A:$$12.05\textbackslash{} \text{a. m.}$$  B:$$12.05\textbackslash{} \text{p. m.}$$  C:$$12.45\textbackslash{} \text{a. m.}$$  D:$$12.45\text{ p. m.}$$  请回答其中一个选项.