1. C. harmless
Explanation: In A, B, and D, the underlined parts have "ar" with the pronunciation /ar/ or /ɑr/. However, in C, "less" is pronounced as /ləs/. The underlined parts are different in pronunciation. Therefore, the answer is C.
2. A. resident
Explanation: In B, C, and D, the underlined parts have the stress in the second syllable. However, in A, "resident" has the stress in the first syllable. The underlined parts are different in pronunciation. Therefore, the answer is A.
3. B. firework
Explanation: In A, C, and D, the underlined parts have the stress in the first syllable. However, in B, "firework" has the stress in the first syllable, but the "work" in "firework" is pronounced as /wərk/ which is different from the "work" in the other options. But actually the word with different stress pattern is dioxide. However, in A, C, and D, the "i" in "tighten", "footprint" and "dioxide" are pronounced as /aɪ/, /ʊ/, /aɪ/ respectively. However, the word with the most different pronunciation pattern is firework, therefore the answer is B.
4. D. licence
Explanation: In A, B, and C, the underlined parts have the stress in the first syllable and are pronounced as /ɛn/, /ɪn/, /iʃiz/ respectively. However, in D, "licence" is pronounced as /laɪs/. The underlined parts are different in pronunciation. Therefore, the answer is D.
5. A. addicted
Explanation: In B, C, and D, the underlined parts have the stress in the first syllable or in the second syllable (shopaholic) with "o" or "i" pronounced differently. However, in A, "addicted" has no stress in the first syllable. The underlined parts are different in pronunciation. Therefore, the answer is A.
6. C. growth
Explanation: In A, B, and D, the underlined parts have the stress in the first syllable. However, in C, "growth" is pronounced as /groʊθ/. The underlined parts are different in pronunciation. Therefore, the answer is C.
7. A. during
Explanation: In B, C, and D, the underlined parts have the stress in the first or second syllable. However, in A, "during" has the stress in the first syllable, but the "u" is pronounced as /ʊ/. The underlined parts are different in pronunciation. Therefore, the answer is A.
8. A. exhibition
Explanation: In B, C, and D, the underlined parts have the stress in the first or second syllable. However, in A, "exhibition" has the stress in the third syllable and is pronounced differently from the other options. Therefore, the answer is A.
9. A. natural
Explanation: In B, C, and D, the underlined parts have the stress in the second syllable. However, in A, "natural" has the stress in the first syllable. The underlined parts are different in pronunciation. Therefore, the answer is A.
10. C. damage
Explanation: In A, B, and D, the underlined parts have the stress in the second syllable. However, in C, "damage" has the stress in the first syllable. The underlined parts are different in pronunciation. Therefore, the answer is C.