All the following expressions can be used to conclude a reaction paper EXCEPT D. The story is all about
Why the expression
The expression "The story is all about" is not used to conclude a reaction paper. Instead, it seems more like a phrase used to introduce or explain the main focus of a narrative or story rather than to signal the conclusion of a reaction or analysis.
On the other hand, "In conclusion," "To sum up," and "Lastly" are commonly used to signal the final thoughts or summary in a conclusion. When these words are used, the speaker gets an idea of the closure of the paragraph and passage.