Here are the words with their underlined parts pronounced differently from the others in each set:

1. C. villas - The "s" is pronounced as /z/, while the others are pronounced as /s/.
2. A. fridges - The "s" is pronounced as /z/, while the others are pronounced as /s/.
3. B. glasses - The "s" is pronounced as /z/, while the others are pronounced as /s/.
4. C. vases - The "s" can be pronounced as /z/ in some dialects (e.g., American English), while the others are pronounced as /s/.
5. A. rulers - The "s" is pronounced as /z/, while the others are pronounced as /s/.

In summary, the different pronunciations in each set are:
1. villas (C)
2. fridges (A)
3. glasses (B)
4. vases (C)
5. rulers (A)