B
(Part of the reason) (Charles Dichens loved his own novel,David copperfield,)(was_)
主语 后置定语 修饰主语 谓语
(__that____it was rather closely modeled on his own life)
表语从句
翻译: Charles Dichens 喜欢他个人小说David copperfield的部分原因就是这本小说接近他自己的生活
B that 表语从句