It means extreme danger so the answer is B
Answer:
C. After dolphins have been underwater for a long period.
Explanation:
A sentence fragement is an incomplete sentence/thought. In all the rest of the answers, there is a concrete meaning behind what is being saif. However, in C, the write doesn't tell you what happens after a dolphin has been underwater for a long period. Thus, it's an incomplete thought and a sentence fragment.
Thats a metaphor!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
