Answer:
She then sat down in a chair.
Step-by-step explanation:
Rearranging words means putting or arranging the given words in such a way that they make a complete and meaningful sentence. This includes the words to be placed in such a way that all given words are used and the end product is a meaningful sentence.
The given jumbled words are "a/she/sat/then/down/chair/in" which can be arranged to make a new sentence "she then sat down in a chair" or "then she sat down in a chair". But considering there is no comma given or included in the jumbled words, we can assume that the best answer can be "she then sat down in a chair".
Thus, the correct answer is "she then sat down in a chair."