Party coalition is common in a

Step 1: Analyze the question The question asks which party system commonly features coalitions, meaning parties joining together to form a government or contest elections.

Step 2: Explain the concept A coalition is an alliance of two or more political parties that cooperate, usually because no single party wins enough seats to govern alone.

Now look at each party system:

• Zero-party system: There are no political parties, so there is nothing to join in a coalition.
• One-party system: Only one party is legally allowed. No other party exists to form a coalition with.
• Two-party system: Two major parties dominate, and one usually wins an outright majority. Coalitions are rare because they are rarely needed (e.g., the USA, with the Democrats and Republicans).
• Multi-party system: Many parties compete, and it is unusual for one party to win a clear majority. Parties therefore often team up to form a government or to challenge a stronger party (e.g., Nigeria's APC was formed in 2013 by a merger of several parties, and Israel and Germany often have coalition governments).

Step 3: Solution Coalitions are needed when power is spread across many parties, and that is the situation in a multi-party system.

Answer: D. Multi-party system

Exam tip: Link the words: Coalition = Cooperation among many parties. If the question mentions "coalition," think "multi-party." Likewise, "hung parliament" also points to a multi-party system.