Answer:
Spanish Conquisadors
B. didn't hesitate to instantly kill the conquered people
As a result of the Spanish conquests of South and Central America, the native American population suffered a huge decline because the Spanish in their quest for riches would massacre entire peoples with no mercy to establish dominance and capture their wealth.
C. fought wars primarily to gain land and riches
The Spanish fought their wars to bring down kingdoms and take their land and riches to send the riches back to Spain and to attain the lands for the Spanish crown.
Aztec
A. fought wars primarily to take prisoners
The Aztecs were a people who loved taking part in rituals as well as cannibalism. These rituals used human sacrifices so Aztecs would prefer capturing people alive in battle so that they could use them in these rituals. It is said that this was so important that sometimes groups of young warriors would bind together to capture just one prisoner.
D. offered the conquered people to gods as sacrifices
As earlier mentioned, the Aztecs captured prisoners for rituals. In these rituals they would sacrifice the captured people to their gods. They would do so by recreating the myths they had heard about their gods such as creation myths and then act the myth out whilst killing the prisoners. They would also fatten the prisoners up for months so that the there would be enough meat during the sacrifice which most if not all in the settlement would then partake of.