The structural element of the paragraph that is the underlined sentence, and it connect ideas in the text is: C) a piece of evidence of the texts argument.
What is structural element?
A paragraph in writing often consists of a topic sentence, a few supporting sentences, and a conclusion. The statement that has been underlined serves as evidence to support the point stated in the text and serves as a supporting sentence. The author's point of view is reinforced when concrete data, facts, or instances are provided.
For instance the sentence that is underlined may include facts regarding the number of smoking-related deaths that occur each year if the paragraph is discussing the negative impacts of smoking.
Therefore the correct answer is C.