The correct answer is C. Thanks so much.
To find the word which has a different sound in the part underlined, we will analyze the IPA notations given for each word.
36. A. exam (ɪgˈzæm), B. academic (ækəˈdɛmɪk), C. vocational (voʊˈkeɪʃənəl), D. hands-on (hænˈzɔn). The underlined part refers to the stress and vowel sounds. In A, B, and C, the stress falls on the second syllable, while in D, the stress falls on the second syllable as well but all have different vowel sounds, but the only different sound falls on "z" vs "s" on "v" vs "h" and vs "ex" in "exam" vs "hands".
So, D "hands-on" has a different sound in the part underlined.
37. A. leaver (ˈlivər), B. teacher (ˈtiʧər), C. speaking (ˈspikɪŋ), D. research (ˈrisərʧ). The underlined part refers to the first consonant cluster. A, B, C have the same first consonant sound, whereas D has a different first consonant sound.
So, D "research" has a different sound in the part underlined.
38. A. degree (dɪˈgri), B. provide (prəˈvaɪd), C. graduate (ˈgræʤəwət), D. doctorate (ˈdɑktərət). The underlined part refers to the stress and first vowel sounds. In A and B, the stress falls on the second syllable, while in C and D, the stress falls on the first syllable, and also, A, B have different first vowel sounds.
So, A, B "degree", "provide" have different sounds in the part underlined.
39. A. pursue (pərˈsu), B. student (ˈstudənt), C. university (junəˈvərsəti), D. institution (ɪnstɪˈtuʃən). The underlined part refers to the first vowel and first consonant sound. A has a different first consonant and first vowel sound, but a different "u" sound is shared with C.
So, B, C, D, "student", "university", "institution" share a different sound with each other.
40. A. chemist (ˈkɛmɪst), B. bachelor (ˈbæʧələr), C. mechanic (mɪˈkænɪk), D. architect (ˈɑrkətɛkt). The underlined part refers to the first vowel sound and first consonant sound. A and B have the same first vowel sound, whereas C, D have a different first vowel and "m" vs "k" vs "b", "ar" sounds.
So, A, B "chemist", "bachelor" have different sounds in the part underlined.