whAt is thE Cost，in CEnts，oF using A CErtAin FAx mAChinE to sEnD n pAgEs oF A rEport iF thE totAl Cost For sEnDing thE First k pAgEs is r CEnts AnD thE Cost For sEnDing EACh ADDitionAl pAgE is s CEntsAssumE thAt n＞k．)
A、r+s(n-k) B、r+s(n+k)
C、rs(n+k)
D、kr+s(n-k)
E、kr+ns