Choose the word (A, B, C or D) whose underlined part is pronounced differently from the others

I. Choose the word (A, B, C or D) whose underlined part is pronounced differently from the others( mọi người giải thích tại sao chọn đáp án giúp mình)
1. A. count B. found C. could D. sound
2. A. happens B. rains C. cancels D. stops
3. A. surround B. course C. mountain D. house
4. A. although B. whether C. ethnic D. clothing
5. A. books B. exams C. texts D. stops
6. A. Malaysia B. media C. majority D. occasion