During which conflict did James Shields serve as a General?

James Shields served as a General during the Civil War, which took place from 1861 to 1865. Shields was initially a notable political figure who had a significant military career, particularly in the Union Army. He took command of various regiments and was involved in key battles, demonstrating leadership and strategic acumen during a critical period in American history. His experience in the Civil War is what established his legacy in military service, and he is remembered for his contributions during this tumultuous time.

The other conflicts listed occurred after Shields' notable military service: World War I happened from 1914 to 1918, the Spanish-American War took place in 1898, and World War II spanned from 1939 to 1945—the latter two being decades after his involvement in the Civil War. Therefore, C is the accurate answer regarding James Shields' military service.