W-2 FROM S-CORP

Hello and thanks for help.

I am going to file my S-Corp 1120-S, and I have a w-2 with 401-k from s-Corp I have some quessions:

1- Should I enter box 1 amount for compensation for officer or box 3

2- for 401-k amount box 12a D , what should I do on 1120-S forms?

3- For IRS side my reasonable compensation is box1 or box3?

really appreciate it for your help.