Final answer:
7 a fabulous b packet c asset d canal. The word 'a fabulous' is the one in which the underlined part is pronounced differently from the others.
Step-by-step explanation:
The word that has a different pronunciation for the underlined part is a fabulous. In this word, the underlined part 'fa' is pronounced as /fæ/ while in the other words, the underlined parts are pronounced as /və'raɪəti/ (a variety), /ə'fɔrdəbəl/ (affordable), and /'nɛɡətɪv/ (negative).
Similarly, in the other words, the underlined parts have consistent pronunciation with the rest of the word. For example, in word 2, 'hum' is pronounced as /hjuːmər/, and in the other words, the underlined parts are pronounced as /'hɪstəri/ (history), /'aʊɚ/ (hour), and /'hupi/ (hoopy).
To summarize, the word 'a fabulous' is the one in which the underlined part is pronounced differently from the others.