Here are the answers for the pronunciation differences:

1. **A. wash** - The "a" in "wash" is pronounced as /ɒ/. The other words have different vowel sounds.
2. **C. salt** - The "a" in "salt" is pronounced /ɔː/, while the others contain the "au" sound pronounced differently.
3. **D. door** - The "oo" in "door" is pronounced as /ʊə/, while the others contain different vowel sounds.
4. **A. broth** - The "o" in "broth" is pronounced as /ɒ/, while the others are pronounced differently.
5. **C. yogurt** - The "yo" in "yogurt" is pronounced differently compared to the "o" in "hot," "another," and "problem."

So the words with differently pronounced underlined parts are:
1. A
2. C
3. D
4. A
5. C