Who was the 25th president of the United States, known for his efforts to unify conflicting interests and support from Mark Hanna?

The 25th president of the United States was William McKinley, known for his leadership during a time of significant national growth and economic change. McKinley's presidency was characterized by his ability to navigate conflicting interests, particularly between labor and business, as well as his efforts in expansionism and responding to the challenges of a rapidly industrializing nation.

His close partnership with Mark Hanna, a prominent businessman and politician, was instrumental in establishing a strong support network for McKinley’s campaigns. Hanna's influence helped unify the Republican Party and played a critical role in securing McKinley's election in 1896 against the backdrop of economic distress, highlighting his ability to rally various factions under a common cause. McKinley’s policies, which included support for protective tariffs and an expansionist foreign policy, further cemented his leadership during a transformative period in American history.

In contrast, the other options represent different presidents who, while significant in their own rights, did not serve as the 25th president or directly align with the context provided in the question regarding McKinley’s unifying efforts and connections with Mark Hanna.