Final answer:
Option D, the Spanish forced labor in mines resulting in the deaths of the Amerindian population, best illustrates the argument described in the passage. Therefore, the correct option is D.
Step-by-step explanation:
The argument described in the passage above is best illustrated by option D: the Spanish forced labor in mines resulted in thousands of deaths of the Amerindian population. The passage mentions that the Spanish clergy interceded to protect the exploitation of Indians in mining operations, which points to the forced labor and its detrimental impact. This argument aligns with the information provided in the passage and highlights the consequences of Spanish colonization on the Amerindian population.