A benefit that is present in all forms of economic integration is that

Analyze the question: The question asks for a benefit that is present in all forms of economic integration, from the loosest to the deepest. The key word is "all".

Explain the concept: Economic integration is when countries agree to reduce or remove trade barriers among themselves. The forms, from loosest to deepest, are:

1. Preferential trade area: lower tariffs on selected goods
2. Free trade area: no tariffs among members, but each member keeps its own external tariffs (e.g. AfCFTA)
3. Customs union: free trade plus a common external tariff
4. Common market: customs union plus free movement of factors of production
5. Economic union: common market plus common economic policies (and often a common currency)

Solution (testing each option):

• A. Common agricultural policy: This is found only in deeper unions, such as the EU. A free trade area has no such policy. ❌
• B. The size of the market is widened: Even in the loosest arrangement, member countries gain access to each other's markets with fewer barriers. Producers can sell to a larger customer base, which encourages economies of scale. This applies to every form of integration. ✅
• C. Free movement of factors of production: This begins only at the common market stage. ❌
• D. Common currency: This is found only in a monetary or full economic union (e.g. the Eurozone, or the CFA franc zone). ❌

Correct answer: B. The widened market is the one benefit shared by all forms of integration.

Exam tip: When you see "present in all forms", pick the most basic benefit, the one that does not depend on deeper integration. Trade barrier reduction leads to a bigger market, and that is the foundation of every stage. Remember the ladder: P-F-C-C-E (Preferential, Free trade, Customs union, Common market, Economic union). Features like free factor movement and a common currency only appear higher up the ladder.