I don't think the sentence would make any sense if you would have even tried to put any "tu" in the it.
Answer:
A
Explanation:
Amalia y Grisela están____________ una canción.
writing
writing
write
writing
Hablo (talk) is the answer
Translated:
When I have a conversation, I TALK a lot.
The other two don't really make sense in this sentence.
Miro = I watch
Estudio = I study
Answer:
who were the first muralists in history?