This is the best novel（ ） we have read中间填什么

This is the best novel（ ） we have read中间填什么
This is the best novel（ ） we have read中间填什么

This is the best novel（ ） we have read中间填什么
填that因为名次前面有最高级the best修饰,所以关系代词只能用that