Answer:
The snake means that his poison can kill the body and allow the soul to return to where it came from.
Step-by-step explanation:
The children's classic "The Little Prince" by Antoine de Saint-Exupery revolves around the story of a stranded pilot's encounter with a "Little Prince" from the planet "Asteroid B-612".
The Little Prince's encounter with the "coil of gold" on the barren desert is found in chapter 17. Here, the Little Prince did not know about snakes nor about anything but was courteously conversing with the reptile. When he commented on how powerless the snake is, "u haven't even any feet. You cannot even travel. . ." the snake remarked that "Whomever I touch, I send back to the earth from whence he came."
This reference is to the Biblical notion of man coming from dust and returning to dust when one dies. So, when he said "whence they came" he's talking about the poison that can kill and send men back to the earth.
Thus, the correct answer is the third option.