【单选题】 A <{p data-we-empty-p="" _msthash="20502" _msttexthash="9792887"}>单位收入<{/p}> B <{p data-we-empty-p="" _msthash="20503" _msttexthash="10162568"}>单位利润<{/p}> C <{p}>单位边际贡献<{br/}><{/p}> D <{p}><{font _mstmutation="1" _msthash="20501" _msttexthash="28122796"}>单位边际贡献率<{/font}><{br/}><{/p}>
