The correct anwser is B. It convinced them that Spain's authority was not legal.
As a result from the alliance named "Pacte de Famille" or "Family Compact" between France and Spain and as a compensation from the losses of the attack from Great Britain, France handed over Louisiana and the Isle of Orleans to Spain in November 1762. Great Britain officially conceded Louisiana to Spain in February 1763 as a part of the treaties that ended the French and Indian War.
Spain's first governor Antonio de Ulloa arrived to Louisiana until March 1766. He landed with a small group of troops and kept his distance from the local elite which was mostly conformed by French citizens who rejected the idea of being ruled by Spain.
He kept his distance socially and politically from the leading colonists when he installed the new trade reform eliminating contraband and regulating the fur trade the citizens began the Revolt of 1768
Although Antonio de Ulloa had the former French governor' Charles Phillipe Aubry's help and support he was denied the money and manpower he needed to impose his authority. Antonio de Ulloa was forced to leave New Orleans leaving Charles Phillipe Aubry as acting governor until Alejandro O'Reilly's arrival.
Because Charles Phillipe Aubry was the former French governor, the citizens of Louisiana thought they had the power back and that Spain's authority was not legal, but Alejandro O'Reilly was able to establish Spain's authority with Aubry's help and military force.