Which statement best explains how political parties are able to exert influence over u. s. public policy?

a. parties persuade voters to support certain policies by using media campaigns and advertising.

b. party members at different levels of government act independently when implementing policy.

c. party leaders encourage members to take nonpartisan positions on most policy issues.

d. parties set policy goals for members to prevent them from being influenced by special interests.

The answer to the question: Which statement best explains how political parties are able to exert influence over U.S. public policy, would be, the one offered in option A: Parties persuade voters to support certain policies by using media campaigns and advertising.

Explanation:

In the U.S system of government, the way that people exhert their control and power over the way the government is run, is through the election of the representatives they will have in the legislative branch, which is the one that makes all the laws and policies. Given this power that voters have, on which member will arrive in Congress, and these representatives belong to parties, the way that parties convince the people to vote for their own members to Congress, and support their legislative actions, is through campaigning and advertising, showing the people that backing up a congresman´s, or a political party´s agenda in Congress, will be beneficial for them.