Question

Choose the answers to the question using a direct object pronoun instead of a direct object noun. There may be more than one answer. ¿Estás coleccionando sellos?
Sí, colecciono sellos.
Sí, los colecciono.
Sí, los estoy coleccionando.
Sí, los coleccionando.

Answer 1

Yes, I collect stamps.
Yes, I collect them.
Yes, I am collecting them.
Yes, collecting them.

Answer 2

I believe "Sí, los estoy coleccionando" would be the correct answer. I can't say that it IS correct but I'm highly confident.