Which of the Following Was NOT One of Philip II's

Which of the following was NOT one of Philip II's military reforms?

A) He abandoned the phalanx formation as too ineffective and inefficient.
B) He made use of cavalry contingents in breaking the opposing line of battle.
C) His warriors used a longer thrusting spear, double that of the Greek hoplite.
D) He made use of engineers who designed catapults to destroy enemy fortifications.
E) His infantrymen carried smaller shields and shorter swords than Greek hoplites.