Hola Russ
If you use "con la que trabajaba..." it doesn't necessarily imply that you work for that company, i.e you are an employee. It is a bit vague, so it could mean that or also that you get involved with that company to do some kind of work. It is a lot more accurate to use "para la que trabajaba". I have changed that option from the answers so there is no confusion.
I hope this helps
Inma
