Mark the letter A, B, C, or D to indicate the correct arrangement of the sentences to make a meaningful dialogue in each of the following questions.

a. What's ASEAN?............b. Cool! Does Vietnam join other groups too?............c. Hey, did you know Vietnam is in ASEAN?............d. Yep, they're also in the United Nations.............e. It's a group where countries in Southeast Asia work together.............f. Wow, that's interesting!