下列哪些情况采用封闭式安全阀（）

A.压力很高

B.有毒介质

C.易燃介质

D.污染环境介质

Wat is NOT required in the radiotelephone log?（）

A.Distress and alarm signals transmitted or intercepted

B.Times of beginning and end of watch period

C.Routine navigational traffic

D.Daily statement about the condition of the required radiotelephone equipment