Simple, it squirts out the dark ink from its body, that spreads quickly in the water and then it is very difficult to see past it, while they attacker is wondering where it went, the octopus swims away quickly
D - Hansel and Gretel must find a way to escape from the witch.
While answer A shows a conflict, their major conflict is with the witch. B is incorrect and they don't have any decision to make whether or not to stay and C is never mentioned in the text.
Fragment...because they are not telling what kind of <span>special</span> creatures.
The answer is B. Although it may seem the other answers are correct as well, in fact they are not. A 'complex paragraph' is indeed one which explains multiple sides of an issue, but favors one, thus only one main topic is represented. It doesn't really matter where the topic sentence is placed - it can be anywhere in the paragraph. However, it is traditionally placed in the first sentence, although that rule isn't written in stone - the topic sentence can also be placed at the end of the paragraph. Therefore, we are left with only one option, and that is B, 'a paragraph should have one main topic'.