Answer: I would say that sentence C uses excessive repetition.
Step-by-step explanation:
Sentence C can be shortened considerably by removing the last two "When they come" phrases and combining the three sentences into one. It would then become, "When they come, I will bolt the door, stand my ground, and fight." Compared to the other options, and considering that sentence C repeats a set of three words three times, it is the most repetitive. (Option A repeats "listened" three times, but that's only one word that's repeated. Option B does not have any repetition, and option D repeats "I," but not in an overly excessive manner.)