The correct answer is Singapore. ASEAN, the Association of Southeast Asian Nations, was founded on 8 August 1967 through the Bangkok Declaration, signed by five countries: Indonesia, Malaysia, the Philippines, Singapore and Thailand, as documented on ASEAN's own official history page. The Philippines, alongside these four partner states, sought to promote regional political stability, economic cooperation and cultural collaboration during a period marked by Cold War tensions and concerns about communist expansion in Southeast Asia, making the founding a significant diplomatic milestone for the region. Singapore, which had only recently separated from Malaysia in 1965 and was still establishing its own international identity, joined the founding group as a small but strategically located city-state at the tip of the Malay Peninsula. Vietnam (option A) is incorrect because it did not join ASEAN until 1995, nearly three decades after the founding, following its post-war reconstruction and Doi Moi reforms. Brunei (option B) is incorrect because it joined ASEAN only in 1984, shortly after gaining full independence from British protection, making it the sixth member rather than a founder. Myanmar (option C) is incorrect because it joined even later, in 1997, alongside Laos, well after the organisation's initial expansion phase. A common exam confusion is assuming any well-known Southeast Asian nation must have been present at ASEAN's founding simply because it is prominent in the region today; founding status is a fixed historical fact tied only to the five 1967 signatories. Revision takeaway: memorise the five founders as a single group, Indonesia, Malaysia, Philippines, Singapore and Thailand, using the acronym-style device that all five names appear on the original Bangkok Declaration.
