Answer:
"Yo vengo de"
Explanation:
"¿De dónde vienes?" means "Where do you come from?"
"Nosotros venimos de" means, "We come from..." Who is we? So this one is incorrect.
"Tú vienes de" means, "You come from..." If someone is asking YOU, why would you say, "You come from..." This is incorrect.
"Ellos vienen de" means, "They come from..." Again, who is they? He/She is talking to one person which is you. This is incorrect.
"Yo vengo de" means, "I come from". This is the proper way to respond
