While is subordinating conjunction
<span>Rev. Hale. He wants to save their lives.</span>
Truth be told, it could be two. A would make sense in that the way the sentence is worded, the turtle herself seems weak. while C is also true to the word dragging as that would make it's movements awkward and difficult. I'd say your best bet would be C as turtles heavy backs and it's slowly speed would make the term "Dragging" make more sense.
I could speak about an anecdote that occurred to a friend of mine while she was presenting her final exam to graduate as a teacher in ESL. She prepared carefully all the theory about the benefits of the use of last technologies and when she was about to start her presentation she discovered that the usb device had been left at home. Can you imagine?
