Janissaries Became More Important Than Cavalrymen in the Late Sixteenth

Janissaries became more important than cavalrymen in the late sixteenth and early seventeenth centuries occurred because

A) horses had become too expensive to use in large numbers.
B) battlefield success increasingly depended on cannon and lighter-weight firearms.
C) Janissaries began to ride horses.
D) Janissaries were from Anatolia, while cavalrymen were mostly from the Balkans.
E) Janissaries had ties to powerful noble clans.