I think it is English at 1.5 billion people
Your answer that you are looking for is genes so its a genes
B if the author can present....
Since the instructions say use the last simple negative form, these are the answers:
1. David did not watch
2. Carol did not appear
3. did not book
4. did not close
5. did not follow
6. did not disappear
7. did not wait
8. did not recognize
9. did not identify
10. did not apologize
11. did not like
12. did not admit