in the 1970s和in the 1970's有区别吗?
（2008浙江）_____,Coca-cola began to enter China's market.
A.In 1970's B.In 1970s
C.In the 1970's D.In the 1970s
答案貌似给的是D唉,可是我看到好多地方也有用到C的那种说法呢,各位大哥大姐前辈们,请问这是为啥啊?