Answer: The correct answer is : Because he took the men from Pemberton and Forrest so that Ulysses S. Grant's troops had the facility to move downstream.
Explanation: Grant is one of the most important generals in the history of the United States. The incursion of Grierson was the most effective of the civil war of the United States, ordered by Benjamin Grierson a brilliant commander of cavalry. The incursion was against the Confederate fortress of Vicksburg on the Mississippi River.
