How Did the Encomienda System Function

How did the encomienda system function?

A) The Spanish crown granted conquerors the right to employ or demand tribute from groups of Native Americans in exchange for providing food and shelter.
B) The Spanish crown gave the colonists groups of Native Americans as legal slaves in return for tax revenues and promises of obedience.
C) The Spanish crown adopted the Native Americans as "protected children" in return for promises of labor and tribute.
D) The Spanish crown placed the Native Americans under the protection of the Catholic missionaries as long as they learned and embraced the Catholic faith.