The paragraph that provides the best variety in sentence patterns is C. Early in the morning, we visited the battlefields at Gettysburg. The Underground Railroad sites we saw in the afternoon were fascinating. I also enjoyed our evening paddle boat ride on the Susquehannah River.
In this paragraph, the structure of the sentences is more varied since it changes from sentence to sentence. In the first sentence, the use of the adverbial at the beginning provides the setting. In the second sentence, the structure used is passive voice. Finally, the last sentence is a simply sentence containing only one verb.