フリー問題

問題文

The alphabet that is safe for a filename and for an address replaces the last two characters of the ordinary one. Which grounds does the specification give for the characters that it turned down?

選択肢

1. A tilde carries a special meaning in some file system settings, and a full stop is unattractive where more than one of it is barred.
2. A tilde carries a special meaning in some naming system settings, and a full stop is unattractive where more than one of it is desired.
3. A tilde carries a special meaning in some file system settings, and a full stop is unattractive where more than one of it is desired.
4. A tilde carries a special meaning in some naming system settings, and a full stop is unattractive where more than one of it is barred.