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 would be d) an analysis of a poem
D, because Odysseus tells the cyclopes that his name is nobody.
The answer is "e" I'm pretty sure. Reading to others can definitely help people develop a greater ability to express oneself verbally.
Hope this helps!