Answer:
A. William Howard Taft
Explanation:
He is the only President ever to do this.
It is William Howard Taft.
William Howard Taft served as the 27th US president between 1909 and 1913. In 1921, he was appointed Chief Justice of the Supreme Court by president Warren G. Harding. He is the only person who has served as both US president and Chief Justice.
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