Sort of depends on how old she is, how well she eats and whatnot.
What I did to determine what vitamins I needed was track my food intake in Fitday, an online nutrition and calorie counting program. I looked at a two month average of my nutrition.
It told me I was deficient in certain vitamins despite eating a well- rounded diet. Mainly C, D, E, Calcium, Iron, and potassium.
So choosing a vitamin for me depended on the RDA values for those vitamins. I looked up the RDA for each, and chose one multivitamin that worked for me. Personally, I chose a high-potency vitamin because it had the complete RDA for iron, 18 mg.
You are supposed to choose a vitamin that will be absorbed well, it should say it on the bottle.
Here is a link I found that is more comprehensive:
Tips For The Savvy Supplement User: Making Informed Decisions And Evaluating Information