Which of the following is the correct Thai word for "thank you"?

The correct Thai word for "thank you" is ขอบคุณ (khob khun). This term is a polite expression of gratitude used in various contexts, conveying appreciation towards someone for their actions or assistance. In Thai culture, expressing thanks is essential for building good relationships and showing respect.

The other options lack the meaning associated with gratitude. ไม่ (mai) translates to "no" or "not," which does not convey thanks. สบายดีไหม (sabai dee mai) means "are you well?" and is used to inquire about someone's well-being rather than to express gratitude. กรุณา (karuna) means "please" or "to be kind," which, while polite, is not a direct expression of thanks. Understanding these distinctions is vital for effective communication in Thai.