Final answer:
The current party system that is becoming more common is the Multiparty system, allowing diverse political representation in democratic countries.
Step-by-step explanation:
The question relates to party systems within political science, a subfield of Social Studies. The correct answer to the question is (a) Multiparty system, which is an example of a current party system. Multiparty systems are characterized by the presence of several political parties that have the capacity to gain control of government offices, separately or in coalition. It allows for more diverse representation and is common in many democratic countries around the world. In contrast, a single-party system is one where only one political party has the right to form the government, generally found in nondemocratic states.