Answer: B) Dramatic irony.
Explanation: an irony is a state of affairs or an event that seems contrary to what one expects and it often has an amusing result. A dramatic irony is when the audience is aware of something that the characters of the story ignore. In the given excerpt we can see a clear example of a dramatic irony, because the audience is aware of the destructive weapon repairing itself, while the space travelers (the characters) don't know it.