what surprised me was not what he did but ---he said it .为什么

答案是a. the way
这里是not...but...并列结构,意思是“不是...而是...”
what he did 是一件事,the way he said it是说这件事的方式.
in the way that和in the way 是介词短语,用作状语.而本句中not...but...连接了两个表语.