C. It puts emphasis on the paragraph's main proposal and call to action.
The stranger's interaction with Elisa at her garden is different from Henry's interaction with her at her garden. The stranger's interaction with Elisa was a bit awkward since they were not introduced formally and Elisa was a bit professional as she entertains the stranger. On the other hand, Elisa was comfortable with Henry since they have been friends for a while already.
I am very sorry if this is wrong, but I think your answer should be, <span>A.She will write a thesis statement to answer her essential question.
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