The primary reason the Spanish established Catholic Missions in Texas was C. to establish dominance in the region.
You included no map but based on the topic of the question, this is the most probable answer.
The Spanish established missions in the Americas to:
convert the Native Americans to Catholicism
to dominate certain areas by getting the Natives on their side
to incorporate the Natives into Colonial Spain
The Spanish reached Texas first but the French wanted some influence in Texas and so Spain was worried about her dominance in the region. Spain therefore established missions and bases in Texas to maintain control.
In conclusion, the Spanish missions in Texas were primarily founded to ensure that they establish and then maintain dominance there.
One claim I can make is that slavery was brought on by the fact that Americans did not want to pay for labor. Another claim is that colonial white Americans saw people of darker skin colors as property, and not actual people, which is what they are.
