Choose the word that has the underlined part pronounced differently from the others

Here are the words with the underlined parts pronounced differently from the others:

1. **Fast** (C) – the "a" is pronounced as /æ/ (as in "cat"), while others include the "a" pronounced as /ʌ/ or /ɔː/.
2. **Sharpener** (B) – the "sharp" part has a different vowel sound compared to the other words.
3. **Compass** (A) – the "com" is pronounced differently than in the other words.
4. **Calculator** (A) – the "ca" is pronounced differently from others that use similar vowel sounds.
5. **Judo** (D) – in this group, each word has varying vowel sounds, but "judo" is distinct from the others.

If you need to know specifically about each group's odd one out, please let me know!