Which best describes how diction contributes to a writer's style?

Diction is the dialogue a writer uses to develop characters.

Diction is the way that a writer varies sentence structure.

Diction is the manner in which a writer arranges words and phrases.

Diction is the language a writer chooses to express an idea.

"Diction is the language a writer chooses to express an idea" best contributes to the writer's style. It is through diction that words are carefully chosen to convey what the writer wants, especially in character dialogues, settings and events. It is through proper diction that literal and inferred meanings can be differentiated.