Choose the word whose underlined part differs from the other three in pronunciation. A.product B.usual C.customer D.lucky

To find the word whose underlined part differs from the other three in pronunciation, we need to analyze the IPA notation of each word. The underlined part is not explicitly given in the question, but we can assume it refers to the vowel sound in each word. A. product: ˈprɑdəkt (the vowel sound is ɑ and ə) B. usual: ˈjuʒəwəl (the vowel sound is u, ə, and ə) C. customer: ˈkəstəmər (the vowel sound is ə) D. lucky: ˈləki (the vowel sound is ə and i) From the IPA notation, we can see that words A, B, and C have a schwa sound (ə) or a similar vowel sound (ɑ, u), while word D has a distinct "i" sound, which is different from the other three words. However, if we consider the underlined part to be the first vowel sound of each word, we can see that words B, C, and D all start with a similar sound (u, ə, or a short u-like sound in lucky, which is often pronounced more like "luh-kee"), while word A starts with a distinct "ɑ" sound. But considering the actual pronunciation in American English, "product" is often pronounced as "ˈprɑdəkt" but in British English it's "ˈprɒdəkt", "usual" is "ˈjuʒʊəl", "customer" is "ˈkʌstəmər" and "lucky" is "ˈlʌki". So "usual" has a "ʊ" sound, while the others have a "ʌ" sound. Considering the most common pronunciations in English, the answer is B. usual.