jiuzhaigou is the most beautiful and fantastic place _i have ever visitedA,that B,where C,which D,what

jiuzhaigou is the most beautiful and fantastic place _i have ever visited
A,that B,where C,which D,what

A
先行词是名词化的最高级形容词,或者先行词被最高级形容词修饰时,用that.