How to choose "Application Type" for I-485?

I asked the following question yesterday but still have got answer yet. I am applying green card for my mother. (I am a U.S, citizen). How should I choose “Application Type” in Part 2 of I-485 form? 同舟共济 said that I should choose (a) and I also checked I-485 Form our attorney filed for my wife 4 year ago and found the attorney also checked (a). But reading the I-485, my understanding that I have to attach a copy of the approval notice but I do not have such an approval notice. What should I do? Simply ignore the request for the copy of the approval notice or select “Other basis of eligibility” and then indicate “File concurrently with I-130”?

Your help would be appreciated. Thanks.