a) Julius Caesar, Alexander the Great, Hannibal Barka
b)
Tran Hung Dao, Tamerlane, Saladin
c) Napolean Bonaparte, Jan III Sobieski, Horatio Nelson
d) Erich Von Manstein, Erwin Rommel, Hans Guderian (my personal opinion - fu
)
Tran Hung Dao - Under his command, Dai Viet (currently Vietnam) armies defeated 2 major Mongolian Invasions in 1285 and 1287. His victories over the mighty Mongol Yuan Dynasty under Kublai Khan are considerably the greatest military feats in world history.
Jan III Sobieski - Grand Hetman of the Kingom of Poland, extremely talented and popular, finally elected as a King of Poland. After a short research I quite sure that he didn't lose any battle. Most important battle he fought is Vienna 1683 - 70 000 of Polish-German soldiers defeated 300 000 Turkish soldiers who were trying to capture city of Vienna. It was his most famous victory, after this battle the Ottoman supremacy in southeastern Europe ended. The most important part of battle was probably charge of Polish hussars (some historians say it was the greatest cavalry charge in history) who smashed Ottoman forces and captured their enormous camp. Nevertheless I have to give some credit to artillery and defenders of the city who also contributed a lot. Battle of Vienna was truly one of greatest victories of European forces over Muslims in history and one of the most important for the fate of the world.