Step-by-step explanation:
1. Ethiopians, who are proud of their great past, are also ambitious for the future. (Option A)
2. If I'd known her address, I would have written. (Option A)
3. I did my homework last night. (Option A)
4. You should see a doctor immediately. (Option B)
5. The woman whose husband won the 2014 Nobel Prize is today's guest of honor. (Option D)