I plan to go back home to visit my family during the Spring Festival, but if I can't get the train ticket, I still

have an________plan: to visit the museums.[ ]

A．alternate  

B．alternative

C．absolute  

D．appreciable

指撇开一切具体形式的无差别的人类一般劳动。它体现着商品生产者之间的经济关系，是劳动的社会属性。