The correct answer is B) Roosevelt split the Republican Party by running as a Progressive.
The factor that led to Taft’s defeat in 1912 was that Roosevelt split the Republican Party by running as a Progressive.
We are talking about the United States Presidential election of 1912. Woodrow Wilson, Governor of New Jersey, was the winner of the election. He was the candidate of the Democratic Party. President Taft lost many votes due to the fact that former US President Theodore Roosevelt competed in the election as a candidate of the Progressive Party, and this caused an important division in the Republican Party.