Which of the following sources would be most helpful to a writer who is trying to properly punctuate an article?

Question

Quizplus · Accepted Answer

A style guide is most useful for determining proper punctuation. It contains a set of standards for the writing and design of documents.
Encyclopedia is incorrect. An encyclopedia is most useful for finding facts on a variety of subjects. 
Almanac is incorrect. An almanac is an annual calendar containing important dates and statistical information such as astronomical data and tide tables.
Thesaurus is incorrect. A thesaurus is a book that lists words in groups of synonyms and related concepts.

Which of the Following Sources Would Be Most Helpful to a Writer