The prefix im- would be correct to create the word impose which means to force something unfamiliar to unwelcome to be accepted/ put into place.
1. January
2. February
3. March
4. April
5. May
6. June
7. July
8. August
9. September
10. October
11. November
12. December
Answer: it is the first one where it says nelson announced the day off demonstrations about the Enviroment to be held on April 22 1970
Explanation: