Extraneous means that something is irrelevant or something that has nothing to do with a particular subject. I hope this helps! :)
Answer:It's mostly talking about how she wants to be able to participate in the Summer Olympics.
Explanation:She is really confident about winning, or getting in to the olympics.
The correct sentence is the second one "She built a high-performance CPU".
The first sentence should not contain a comma and is incorrect. The third sentence is incorrect because there shouldn't be a dash before CPU. The fourth sentence is incorrect because CPU is not written with dashes.