题目内容：
Adeveloperhascreatedawebapplicationthatincludesaservletforeachusecaseintheapplication.Theseservletshavebecomeratherdifficulttomaintainbecausetherequestprocessingmethodshavebecomeverylarge.Thereisalsocommonprocessingcodeinmanyservletsbecausetheseusecasesareverysimilar.Whichtwodesignpatternscanbeusedtogethertorefactorandsimplifythiswebapplication？（）A.Proxy
B.ViewHelper
C.FrontController
D.SessionFacade
E.BusinessDelegate
F.Model-View-Controller
参考答案：