College grad interview clothing...help

Lovely ladies. My DD is graduating next month and a week ago started shopping her resumes out there with people she interned with, networking with contacts she has, etc.

Anyway...for interviews, does a young professional woman have to wear a suit? Would a corporate environment appropriate dress with pumps be okay. What about dress pants, button down shirt, and pumps?

Her internship last January was very formal corporate, so she has nice things we bought for that six week period, but they were separates and a few corporate approrpiate dresses. I just want to know if you think I need to take her out for a formal skirt suit?