The most influential and powerful members of a political party are most likely found in party precincts. at the state party level. among party volunteers. inside the national party.

inside the national party.

The most influential members of a party would be at the national level which is basically the top organ of a party. Party officials at the  most level, which is the national party are able to influence policy and make the major decisions

d is the answer. leo should include the source.