The sentence uses the form dresses in, which is incorrect and needs improvement. Using the preposition ‘in’ is incorrect here, hence it has to be corrected. The correct phrasal verb to be used here is dresses up. To dress up is a phrase which means to wear beautiful clothes. e.g. She loves to dress up irrespective of the occasion. The only alternative that improves the sentence is C. None of the other alternatives can make the sentence meaningful. Therefore, the correct answer is option 2.