Which of the Following Statements Concerning the Nature of Warfare

Which of the following statements concerning the nature of warfare among the bushi is most accurate?

A) The bushi depended on infantry tactics, equipping the samurai initially with long spears.
B) The introduction of gunpowder in the 11th century allowed the bushi to rely on cannons and rockets as their primary means of assault.
C) Battles depended on the Japanese phalanx of mounted samurai and massed assaults predicated on the willingness of the retainers to sacrifice themselves for their leaders.
D) Battles hinged on man-to-man duels of great champions typical of the heroic stage of warfare.