What Tactic Led to the Dutch Control of the Entire

What tactic led to the Dutch control of the entire island of Java?

A) The Dutch won a series of naval battles over forces of the sultan of Mataram.
B) The Dutch introduced African mercenaries into Java to secure a military victory.
C) The Dutch, using mercenary forces recruited from the people of Java, intervened in succession disputes in return for grants of land.
D) The Dutch used the process of conversion of masses of the Javanese people as well as the elite to gain a position of supremacy on Java.