Please help on I-131 Form

Question 1:
Part 1: 3. Class of Admission. I was entered to USA with F-1 visa and now is H1B status, what should I write in?
Question 2:
Part 3: 2. Expected Length of Trip. I'm wondering if the AP has a fixed length (say one year) or depends on what I filled in this section.
Thank you so much for your help!