помогите поставить правильную форму Present Perfect или Past Simple


Interviewer: So why (1) did you apply / have you applied for this position?
David: Well, (2) for / since  the last three years I have been working  in an interesting, but very small, company, and I now feel ready to move on to a bigger challenge. 

So why did you have you applied for this position?Well for the last three years I have been working in an interesting but very small company and I now feel ready to move on to a bigger challenge