Is this research center( )is full of morden equipment you al

C
分析：恢复语序后
this research center is ( )is full of morden equipment you always mentio.
句子中缺少先行词,和关系代词,所以the one做先行词,that 做主语.不能省略
where 不能做主语淘汰D
如果选AB就是表语从句,但是从句中缺少主语,但是AB在表语从句中都不能做主语,所以淘汰AB