The Regional Comprehensive Economic Partnership (RCEP) is a free trade agreement that involves the Association of Southeast Asian Nations (ASEAN) and its FTA partners — Australia, China, Japan, New Zealand, and South Korea. It aims to create a comprehensive economic partnership covering trade in goods, services, investment, intellectual property, and e-commerce.

ASEAN was initially a 10-member bloc consisting of Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand, and Vietnam. In 2025, Timor-Leste (East Timor) formally became the 11th member of ASEAN — marking its first expansion since Cambodia’s inclusion in 1999.

In the 22nd ASEAN-India Summit (2025), both sides endorsed the ASEAN-India Plan of Action (2026–2030), focusing on areas such as maritime cooperation, digital innovation, education, and sustainable development. The year 2026 was declared the ASEAN-India Year of Maritime Cooperation.

Hence, the RCEP continues to be associated with ASEAN and its FTA partners, and the correct answer remains (b) ASEAN.