0. known (C)
1. most (A)
2. Although (B)
3. possibility (A)
4. express (D)
5. These (C)
6. work (A)
7. form (C)
8. examples (D)
9. attempts (B)
10. costs (C)
11. For (C)
12. on (A)
13. remain (B)
14. led (C)
15. for (A)
