This question is based on Literary Principles The choice of words used by a writer in a literary work is called

Diction refers to the choice and use of words by a writer in a literary work. It encompasses the vocabulary, phrasing, and level of formality a writer selects to convey meaning, create mood, and establish tone. Diction can be described as formal, informal, colloquial, archaic, poetic, or technical, among other categories. A writer's diction is one of the most important tools for shaping how readers experience a text.

The other options are distinct literary concepts. A cliche is an overused expression or idea that has lost its original impact through excessive repetition (e.g., "time heals all wounds"). An idiom is a fixed phrase whose meaning cannot be deduced from the individual words (e.g., "kick the bucket" meaning to die). Tone refers to the attitude or emotional quality conveyed by the writer toward the subject matter or audience - tone is a product of diction, not the same thing as diction itself.

When a question asks about a writer's "choice of words," the answer is always diction.