Third parties are similar to interest groups because they

Atend to focus on a single issue
Bdo not run candidates for office
Chave lobbyists in the legislature
Davoid supporting extreme ideas

Verified Answer :

Third parties are similar to interest groups because they tend to focus on a single issue. The correct answer is A.

I believe the answer is: A. tend to focus on a single issue 

Third party is formed because their view is not represented by the two major dominant parties (Democrat and the Republicans), which force them to make a new party of their own. Example of a third party in united states is the Green party which care for environmental issues only.