Slowly _______________ and _________________ outstretched arms indicates an emergency.

The correct answer is "extending, spreading" because this gesture is widely recognized as a distress signal in marine and general safety contexts. When someone extends their arms outward and spreads them, it creates a notable visual cue that can attract attention, signaling to others—particularly those who are trained in emergency responses—that assistance may be needed.

This gesture is often taught in survival training and rescue scenarios, where visibility and clear communication are crucial in emergencies. The act of extending and spreading arms maximizes the area of motion, making it more conspicuous to those who might be onlookers or responders. In contrast, the other options do not inherently carry the same established meaning of an emergency signal, making them less effective in conveying a sense of urgency or distress.