In the context of writing mechanics, which option focuses specifically on how to use words correctly?

The correct choice emphasizes a crucial aspect of writing mechanics, specifically targeting the proper use of words in context. Word usage skills encompass understanding nuances in meaning, selecting appropriate words for the intended message, and applying vocabulary accurately within sentences. Mastering these skills is essential for effective communication, ensuring clarity and precision in writing.

While punctuation and capitalization skills involve the rules governing the correct placement of symbols and letters for grammatical correctness, and sentence-processing skills relate more to structuring and understanding sentences as wholes, word usage skills directly address the choice of words. Style skills focus on the writer's voice and tone, which, although important, do not specifically pertain to the correctness of word usage. Thus, the focal point of this question is definitively on the ability to use words correctly, making the choice about word usage skills the appropriate selection.