All of the following third parties have over 100,00 members except the party.
a. libertarian
b. constitution
c. socialist
d. green

C. socialist

Explanation:

The modern two-party system consists of the Democratic Party and the Republican Party. Several third parties also operate in the U.S., and from time to time elect someone to local office. The largest third party since the 1980s has been the Libertarian Party.

Libertarian Party

It is the largest continuing third party in the United States, claiming well over 500,000 registered voters across all 50 states.

Other examples of a third party is the Green Party, running alongside the Republicans and Democrats.

Socialist Party is the name of many different political parties around the world. ... Statistically, most of these parties advocate either democratic socialism, social democracy or even Third Way as their ideological position. Many Socialist Parties have explicit connections to the labor movement and trade unions.

DeWitt, Samuel Orr, Louis Waldman, Charles Solomon, and August Claessens", the Assembly's five Socialist members

ok sorry the answer is a. by their religion