Which Characterizes Grant's Abilities as a General

Which characterizes Grant's abilities as a general?

A) ruthless in his treatment of enemy soldiers and of civilians in enemy territory
B) a brilliant organizer who could be overly hesitant to commit his troops to battle
C) highly effective in holding territory, but unable to achieve significant advances
D) a cautious and intelligent steward of those under his command
E) a daring yet logical strategist who wasn't afraid to incur high casualties for strategic aims