The words with a different sound in the underlined part are:

1. **A. activity** (the 'i' sounds different from the other options)
2. **B. women** (the 'o' sound is different from the other options)
3. **C. think** (the 'th' sound is different from the other options)
4. **D. cabbage** (the 'a' sound is different, as the others have different vowel sounds)
5. **B. cover** (the 'o' sound is different from the other options)

Thus, the words with different sounds are **1A**, **2B**, **3C**, **4D**, and **5B**.