問題文
The page states how a source of your own is picked up, and it offers two interfaces either of which may be implemented for that. Which pair does the page offer?
選択肢
- Either the interface for a lone source or the interface for a watch that reports a change in a backing store.
- Either the interface for a lone source or the interface for a filter that rewrites a value before it is spotted.
- Either the interface for a lone source or the interface for a reader that turns text of one format into nodes.
- Either the interface for a lone source or the interface for a hand that gives out several of them at once.