Final answer:
The refusal of Pedro I to return to Portugal upon the Portuguese Cortes's orders in 1822 led to the declaration of Brazilian independence, encapsulated by the event known as the Grito do Ipiranga.
Step-by-step explanation:
The Event Precipitating Brazil's Independence
The event that precipitated the declaration of Brazil's independence was d. the refusal of Pedro I to obey the Portuguese Cortes's order to return to Portugal in 1822.
This refusal marked a significant moment in Brazilian history known as the O Fico. Influential for the political climate of the time were the tensions generated by the Cortes, which sought to reduce Brazil to its former colonial status and dismantle Rio's central government structure.
The situation escalated when the Brazilian elites, siding with Pedro I, rejected Portuguese rule, leading to Pedro's declaration of Brazilian independence on September 7, 1822, after the impactful Grito do Ipiranga.
The buildup to this event included a series of occurrences that shaped the environment for independence: the French invasion of Portugal, the establishment of the royal court in Rio de Janeiro, and the various demands and conflicts within the Portuguese parliament regarding Brazil's status.
The assertion of independence by Pedro I alongside the political and social circumstances played a pivotal role in Brazil's quest for sovereignty, culminating in the crowning of Pedro I as the Constitutional Emperor of the newly independent Brazil.