D. Shells
You can ignore all of the words after of until the verb (of marine mollusks)
So it's just shells are taken...
You shouldn't trust the information if another source disapproves. You should look more into it, finding several sources with the same information before using anything you find.
B. would be the correct comparison because the others either use wrong term or double comparison like more better. Best would be superlative and used for comparing three or more things. Gooder is not a word. More better is double comparison.
Answer:
Quietly stalk the hunter instead of loudly stalking him
