It's C.
It needs a colon because the following things after make a list
The sentence <em>Sickly people cost the company a whole boatload of dough </em>is not acceptable because the sentence contains a loaded word as well as slang.
You cannot use slang words such as <em>boatload </em>or <em>dough </em>in formal English.
Answer:
drink from the oprned ends of their harpoons.
