A.R=Quk/rs+Qpk/rp B.R=Quk/rsp C.R=ηspQuk/rsp+ηCQCk/rC D.R=ηsQsk/rs+ηpQpk/rp+ηCQCk/rC
A.(2-6)D B.(3-10)D C.(1-2)D D.(0.5-1.5)D
A.1.5D B.2D C.1D D.4D