Final answer:
Duverger's Law indicates that a single-member district with plurality voting often leads to a two-party system, as seen with the Democratic and Republican parties in the U.S. Therefore, the correct answer is A. TRUE.
Step-by-step explanation:
Duverger's Law suggests that single-member district systems with plurality voting tend to favor the development of a two-party system. This phenomenon is due to the 'winner-take-all' nature of elections in these systems, where only the candidate with the most votes wins the seat, discouraging votes for less popular third parties as they are seen as wasted. Hence, A. TRUE is the correct answer to the statement "Duverger's Law states that single-member districts result in two-party systems."
In the United States, for example, the two dominant parties are the Democrats and Republicans. Third parties face significant challenges in trying to break into the system due to the difficultly of overcoming established parties' momentum and resources. By contrast, in countries with proportional representation systems, there is often a greater number of competitive parties.