马克思、恩格斯最重要的理论贡献是（　　） 

A、<p><span style="font-size:16px;font-family: 宋体">A=</span><span style="font-size:16px;font-family:宋体">辩证法</span></p>

B、<p style="line-height: 150%;"><span style="font-size: 16px;line-height:150%;font-family:宋体">B=</span><span style="font-size:16px;line-height:150%;font-family:宋体">劳动价值论&nbsp;</span></p>

C、<p style="line-height: 150%;"><span style="font-size: 16px;line-height:150%;font-family:宋体">C=</span><span style="font-size:16px;line-height:150%;font-family:宋体">唯物史观&nbsp;</span></p>

D、<p style="line-height: 150%;"><span style="font-size: 16px;line-height:150%;font-family:宋体">D=</span><span style="font-size:16px;line-height:150%;font-family:宋体">剩余价值学说</span></p>