Which person served as a Union General during the Civil War?

• A. Matthew Perry
• B. James Longstreet
• C. Abraham Lincoln
• D. Ulysses S. Grant

Answer: (D)

The question asks which person served as a Union General during the Civil War, so you want to name the military leader who fought for the United States rather than the Confederacy. Ulysses S. Grant was the Union general who led major campaigns across the Western and Eastern theaters, earning the Union decisive victories at Fort Henry and Fort Donelson, then at Shiloh, and most crucially at Vicksburg, which gave the Union control of the Mississippi River. He also commanded forces at Chattanooga and ultimately arranged the surrender of Confederate General Robert E. Lee at Appomattox Court House in 1865, effectively helping to end the war. He later became General-in-Chief of the Union Army, shaping its overall strategy.

As for the other options, Matthew Perry was a naval officer famous for opening Japan to Western trade; James Longstreet served as a Confederate general under Lee; Abraham Lincoln was the President during the war, not a general. Therefore, Ulysses S. Grant is the correct choice.