Answer:
D. while candidates have become dependent of on these donations to run increasingly expensive campaigns
Step-by-step explanation:
The financial help provided by interest groups massively increase the chance of a political candidate to win an election. The money mostly used to create series of campaigns that increase the popularity of the candidates (through hiring door-to-door canvasser, advertising board, TV appearances, etc)
This made a lot of candidates become dependent of on these donations to run increasingly expensive campaigns.
But , this come with a massive downside. The interest groups do not give those donations for free. After the candidates win, the interest groups expected those candidates to pass laws that beneficial for the interest groups.