Final answer:
The central idea of the text about Trujillo is the impact of his reign on the Dominican Republic, leading to political turmoil and foreign intervention.
Step-by-step explanation:
The statement that identifies the central idea of the text about the spark that brought down Trujillo is A) The impact of Trujillo's reign on the Dominican Republic. The text describes the political unrest and intervention by foreign powers in the wake of Rafael Trujillo's assassination. It focuses on the broader implications of Trujillo's dictatorial regime, the subsequent liberal reform efforts by Juan Bosch, the counter-revolution by conservative forces, and the U.S. invasion to prevent a perceived communist takeover, ultimately leading to a conservative government in the Dominican Republic.