Here are the answers for each item based on different stress patterns:

1. **A. opinion**
**B. responsible**
**C. attitude**
**D. account**
- **Answer: A** (stress on the second syllable for the others)

2. **A. contents**
**B. continent**
**C. constant**
**D. consider**
- **Answer: A** (stress on the first syllable for the others)

3. **A. horizon**
**B. horrified**
**C. hospital**
**D. horoscope**
- **Answer: C** (stress on the first syllable for the others)

4. **A. cycle**
**B. create**
**C. device**
**D. effective**
- **Answer: A** (stress on the first syllable for the others)

5. **A. dental**
**B. device**
**C. drunkard**
**D. endless**
- **Answer: C** (stress on the first syllable for the others)

So, the marked answers are:
1. A
2. A
3. C
4. A
5. C