单项选择题
A.be fitted with a positive fuel shut-off valve located at the tank
B.have a shut-off valve at the top of the tank
C.have a gate valve easily accessible in the space where the tank is located
D.have a drain cock at the lowest point in the fuel line
单项选择题 Fire protection regulations for towing vessels require all crew members to know how to perform each of these tasks EXCEPT（）.
单项选择题 Fire protection regulations for towing vessels allow all of these types of fuel piping，EXCEPT（）.
单项选择题 Fire protection regulations apply to those towing vessels（）.