Answer :
Answer: D- Some third party goals eventually became platforms in the major parties
Explanation:
The Populist party was a major force in the late 19th century and drew its support from mainly farmers who were angered by the exploitation visited on them by Corporate interests in the country at the time.
In the 19th century, the United States had been using both the gold and silver standards for currency until they abolished the silver and went with just gold. Famers did not like this as they preferred silver and so made reinstating silver a primary goal.
William Jennings Bryan ran on this platform but for the Democratic party and after a very rousing speech (Cross of Gold), galvanised the Democrats behind him and the Populist party then followed suit.
This showed that the goal of the Populist party (a third party) became a platform for a major party(the Democrats).