It's a well-known fact that camels can go for extended periods without water. c)none The fact that camels can go for extended periods without water is well known.

:) it's b) of course

well zara answer is c) none

Zara, I don't like this question. The sentence is poorly constructed. But if I had to make a choice I would go with beta's answer. It's the only one which makes sense without changing the word order in the sentence.

It's well-known the fact that camels can go for extended periods without water.