I think it would be worse
The answer to this question is C, because you cannot have a dependent clause stand alone, and to combine it to an independent clause you'd have to add a comma to the end of it before the independence clause begins.
Answer:
At the time of the Epilogue, she has lived with the Fromes and been cared for by Zeena for over twenty years. Mattie has become querulous, whining, and petulant.
Explanation: