如下UserStory的描述格式哪个是正确的（）

A.Asa< userRole>，Iuse< what>，sothat< Value/benefit>.
B.Asa< system>，systemwantto< Activity>，socan< getValue>.
C.Asa< userRole>，Iwantto< desiredfeature>，sothat< Value/benefit>.
D.Asa< system>，systemwantto< Activity>，sothat< BusinessValue>.