Which of the Following Statements Most Accurately Characterizes Trends in Warfare

Which of the following statements most accurately characterizes trends in warfare in the fourth century BCE?

A) There was greater focus on the hoplite phalanx as the main unit in warfare.
B) There was a decrease in the use of mercenaries.
C) A variety of unit types were incorporated, including light infantry or cavalry.
D) The use of cavalry decreased.
E) Simpler tactics were employed over time.