The correct answer is C) They received Louisiana as a result of the French defeat in the French and Indian War.
The Spanish gained possession of Louisiana when they received Louisiana as a result of the French defeat in the French and Indian.
This happened after the signing of the Treaty of Paris of 1763, signed in the city of Paris, France.
The French had lost the War and they also lost a big portion of the North American territory. Victorious Great Britain got the Quebec territory and the Ohio Valley. The French also lost territories that were given to the Spaniards. They lost the west part of the Louisiana Territory. That is how the British thanked Spain for being its ally during the war.