Read the following passage and mark the letter A, B, C, or D to indicate the correct word or phrase that best fits each of the numbered blanks

ASEAN, which ___(1)___ for the Association of Southeast Asian Nations, is a regional organization composed often countries in Southeast Asia. ___(2)___ in 1967, ASEAN's main objective was to promote cooperation and integration among its member states. It aims to enhance regional peace, stability, and economic growth through various means such as dialogue, diplomacy, and collaboration. ASEAN member countries include Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand, and Vietnam. These nations work together ___(3)___ a wide range of issues, including trade, security, cultural exchange, and social development. They strive to foster closer ties through regular meetings, summits, and the establishment of various agreements and frameworks.
As a diverse and dynamic region, ASEAN offers numerous opportunities for economic development and ___(4)___ exchange. Its combined population of over 650 million makes it one of the largest markets in the world. ___(5)___, ASEAN's strategic location has contributed to its emergence as a hub for international trade and investment.