问题：

[单选] Which statement about immersion suits is TRUE?（）

A . The primary color of the suit's exterior may be red，orange or yellow
B . The suit must，without assistance，turn an unconscious person's mouth clear of the water within 5 seconds
C . The suit is flameproof and provides protection to a wearer swimming in burning oil
D . The suit may be stored in a machinery space where the ambient temperature is 160°F