An informal writing style includes a. longer sentences. b. contractions (for example, wouldn't, don't, they're). c. second-person pronouns (for example, you and your). d. mainly passive-voice verbs.

The correct answer is B. An informal writing style includes contractions (for example, wouldn't, don't, they're).

Explanation:

Contraction is the merging of two words from different parts of speech into a single word. Contractions are generally used more frequently in colloquial language, poetry, in the shortest possible headings and so on than in the standard or written language.

There are a lot of melting words in English, with most of them "swallowing" a vowel, which is then replaced by an apostrophe in written language, such as I'm for "I am". Sometimes there are other changes like won't for "will not". These mergers are mainly used in the spoken and informal written languages and should be avoided in the formal written language.