485 questions, please help!

My I-140 has been approved. I am filing my I-485.

I have two questions, please help.

Question #1: On Form I-485, part 2, Application Type. Which category should I choose:
(a) an immigrant petition giving me an immiediately available immigrant visa number has been approved.
or
(h) Other basis of eligibility.
My question is, although my I-140 has approved, but I have no immigrant visa number due to backlogs. Should I choose (a) or (h)?

Question #2: about "Employment Letter": should I request a new letter or can I use the letter which was used for my I-140 petition?


Thanks in advance for your help.