What are the written signs referred to in John 20:31?

John 20:30-31 >30 And **many other signs truly did Jesus** in the presence of his disciples, **which are not written in this book**: > >31 **But these are written**, that ye might believe that Jesus is the Christ, the Son of God; and that believing ye might have life through his name. ***My question is about verse 31, what are the signs which are written?*** Is it A) what Jesus does in chapter 21, B) what he has done during his life (as recorded by John), or C) is it something else? If it is A, would this be an example of where a chapter breaks up the record (chapters are arbitrary )? If it is C, what are the signs and where does John reference them?