When the independent clauses of the sentences are not joined correctly, they are called run-on. The sentence can be corrected by placing a semicolon between the words things and they. Thus, option D is correct.
What is a semicolon?
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A semicolon is a grammatical mark that shows a separation between the two clauses of the sentence and shows the equal importance of both parts of the sentence.
It is used to correct the run-on sentences so that the unjoined independent clauses can be linked together in a purposeful manner and leads to correct sentence formation.
Therefore, option D. using semicolons corrects the run-on sentence.
Learn more about run-on sentences here:
https://brainly.com/question/696177
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