The correct option is: "I. He had served two terms as a senator"
Rutherford Birchard Hayes was an American politician, lawyer, military leader and the 19th president of the United States between 1877 and 1881. As president, he oversaw the era of the Reconstruction of the United States and restored confidence in the government. He was a reformer who carried out the reform of the civil service and tried to reconcile the divisions inherited from the Civil War and Reconstruction.