Tu because If you put Mi or mis son rojos it says my are red which dosen't really make sense. Since you put tu in front of son (plual) it would be they are red.
Are you wanting to translate into English? If so, it's Eduardo hurts his elbow.
Answer:
Explanation:
6. Uds. _ están_ nerviosos.
7. Hoy _ es _ el nueve de octubre.
9. La mochila _ es _ de Miguel.
10. Ud. _ está _ contento.
The answer for a is 1 and for b is 4 and c is 2 and d is 3. I know Spanish and I speak so it was pretty easy, hope this helps! A-1 b-4 c-2 d-3
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