The correct answer is B) He wanted to keep the Army of Northern Virginia from invading the North again.
Grant's main strategy during his Overland Campaign was to help work toward the defeat of the Confederacy in that "he wanted to keep the Army of Northern Virginia from invading the North again."
The Union Army conducted a series of battles in the territory of Virginia that tried to stop the advancements of the Confederate Army led by General Robert E. Lee.
Union's Army General Ulysses S. Grant ordered his troops during May and June 1864, to defend their positions. The renowned Army of the Potomac led by General George G. Meade offered great opposition to finally get a strategic advantage despite losing many men in the battles. The troops of General Lee also suffered major losses and damages.