Which of the following is an example of expository writing, that is, writing that explains, informs, or describes facts about a topic?

Introduction / Context:
This question tests your understanding of different modes of writing, especially expository writing. In school and college, you frequently read and write different kinds of texts: stories, poems, reports, essays, and reviews. Correctly identifying whether a text is expository, narrative, descriptive, or persuasive is an important reading skill and a frequent exam topic.

Given Data / Assumptions:
- We are asked to select an example of expository writing.
- Expository writing aims to explain, inform, or describe facts, processes, or ideas in a clear and logical way.
- The options include a novel, a nonfiction book, a poem, a movie review, and a short story, all related to the Civil War topic.

Concept / Approach:
Expository writing usually presents facts, explanations, or information without focusing mainly on storytelling or personal opinions. Typical examples include textbooks, informative articles, reports, and explanatory essays. In contrast, a novel or short story is narrative, a poem is often lyrical or expressive, and a movie review is mostly evaluative and opinion based, even though it may contain some information.

Step-by-Step Solution:
Step 1: Identify which option is most clearly written to explain facts about the Civil War rather than to tell a story or express feelings.
Step 2: Notice that a nonfiction book about the history and causes of the Civil War matches this purpose exactly.
Step 3: Recognise that a novel, poem, or short story uses narrative or poetic techniques and is not mainly expository.
Step 4: Recognise that a movie review focuses on judging and evaluating a film, which is more persuasive or critical than expository.

Verification / Alternative check:
If you imagine reading each type of text, the nonfiction book about the history and causes of the Civil War would probably contain dates, facts, explanations of reasons, and analysis of events. It would clearly try to teach you something about the topic. The novel and short story would focus on characters and plot. The poem would focus on emotional or artistic expression. The movie review would give opinions about acting, direction, and quality of the film. Thus, only option b fits the expository purpose strongly and directly.

Why Other Options Are Wrong:
- A novel about a young girl: narrative fiction, mainly storytelling.
- A poem about soldiers: poetic and expressive in nature, not primarily expository.
- A movie review: evaluative and opinion based, often persuasive.
- A short story: another example of narrative fiction focusing on characters and events.

Common Pitfalls:
Students sometimes think that any nonfiction or any text containing facts is automatically expository. However, the key is the main purpose. If the primary goal is to explain, inform, or describe a topic objectively and systematically, then it is expository. If the main goal is to tell a story or to convince the reader, it falls into other categories. Here, the nonfiction history book is clearly informational in purpose.

Final Answer:
The expository example is a nonfiction book about the history and causes of the Civil War.