Answer:
Sympathetic
Explanation:
The sympathetic system is a nervous system which makes the body to stay alert and directs the body to be vigilant. It can be considered as an involuntary response towards potential danger or a response to a stress. This is done by directing extra blood to the limbs and by increasing the heart rate. Here, Otto is being extra vigilant and his body is on alert for danger and therefore, the answer is sympathetic system.