[求助]白勇语法书上的一道题目求解

founded in 1983, the magazine increased its circulation more than double since then, and its advertising.

A. increased its circulation more than double since then

B. has since increased its circulation more than double

C. has since more than doubled its circulation

D. since then more than doubled its circulation

E. more than doubled its circulation since then

答案给的是第三个，我知道看到since then 应该使用完成时态，但是c选项怎么看怎么不像啊，求助大家分析一下c选项，主谓是magazine has doubled circulation，但是那个since more than怎么理解呢

先谢谢大家了

since这里应该就是一个副词“从那时到现在”

I left school last year and has stayed at home ever since.

啊，楼上的jingjin一解释顿时明白了，原来since是跟founded产生联系

是啊，解释的太好了！！！