フリー問題

問題文

A visit context is asked which client ids under a naming container are worth visiting. What comes back when there are none of them, and what comes back when the whole subtree is to be visited?

選択肢

1. With none of them worth visiting the call gives back an empty gathering, and with the whole subtree to visit it gives back the sweeping token
2. With none of them worth visiting the call gives back a hollow answer, and with the whole subtree to visit it gives back the outermost token
3. With none of them worth visiting the call gives back an empty gathering, and with the whole subtree to visit it gives back the outermost token
4. With none of them worth visiting the call gives back a hollow answer, and with the whole subtree to visit it gives back the sweeping token