The correct answer is B. She spent four days trying to put together the perfect outfit in the end, she settled for something simple: a black tee, ripped jeans, and a headband.
Explanation:
Colon (:) is a punctuation sign just as a comma (,) or a question marks (?), this punctuation sign is usually used before a list of items that are related to the previous sentence, but colon can also be found as a sign to introduce an explanation, a quotation or an example. In this case this sentence contains a list of items "a black tee, ripped jeans, and a headband" that are related to the previous sentence "she settled for something simple", considering this the use of colon (:) to introduce the list of items is grammatically correct and this is the only sentence that uses colon according to grammar rules that set colon should be used to precede a list, example, quotation or explanation.
