While the main idea is usually in the first sentence, the next most common placement is in the last sentence of a paragraph. The author gives supporting information first and then makes the point in the last sentence. Here's a paragraph we can use as an example. Try to locate the topic and the main idea.
The answer is : D
Because antonyms means the opposite of something.
Where it is in the sentence, how it is used, and the meanings of words surrounding it.