In which case would an overtaking vessel sound a whistle signal of two prolonged followed by one short blast?

A、Whenovertakinginrestrictedvisibility.
B、Whenovertakinginanarrowchannel（RULE343（1）2长1短：我船企图从你船右舷追越；（2）2长2短：我船企图从你船左舷追越）
C、Whenovertakingonopenwaters.
D、Whennoothervesselsareintheimmediatearea.