The 1912 Republican convention was an ideological contest between

both different types of progressivism and the "New Freedom" and "New Nationalism."
the Old Guard and what was to become the "Bull Moose."
La Follette and Taft. All these answers are correct.
the "New Freedom" and the "New Nationalism."

The correct answer is the Old Guard and what was to become the "Bull Moose."

Explanation:

This convention was held at the Chicago Coliseum, confronting William H. Taft and Vice President James S. Sherman for reelection. This only meant the beginning of a process of split within the republican toldas, since there was a marked dispute for power that was carried out by William H. Taf and Theodore Roosevelt. Bull Moose was a party that was created after this dispute, where Roosevelt lost the nomination.