Here are the answers based on the pronunciation of the underlined parts:

1. **C. gymnastic** (The "gym" is pronounced with a soft 'g', unlike the hard 'g' sounds in the other words.)
2. **D. geology** (The 'geo-' in geology is pronounced with a hard 'g', while the other words have a soft 'g' sound.)
3. **C. chain** (The 'ch' in chain is pronounced as /ʧ/, while the other words have different sounds for 'ch'.)
4. **D. July** (The 'Ju' in July is pronounced as /dʒu/, which is different from the other words.)
5. **C. cheap** (The 'ch' in cheap is pronounced as /ʧ/, while the other words have different 'c' sounds.)

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