C.
since it does not use proper punctuation to combine to thoughts
What story is it that this 'passage' came from?
Answer:
We don't have the text to answet this.
Explanation:
<span>after sentence 6 to support the topic sentence
This sentence shows a specific way that researchers are working on solar power. It also sets up the rest of the paragraph that shows how and why solar power is such a good alternative to fossil fuels. </span>
