Choose the best answer (A,B,C or D) to complete each of following sentences.
1. B. in danger
2. B. pollution
3. A. coexist
4. B. interfered
5. C. influence
6. B. from which
7. D. that
8. B. That
9. C. in which
10. A. in whom
11. C. with which
12. A. on which
13. C. to which
14. B. that
15. C. to which