F (Green) is my choice!!
The following are the points in her favor:
1. She has a beautiful smile, but its not a big model-like smile, or any enticing kind, but more simple and friendly.
2. Her glasses give her the studious look but in a very pleasant way
3. Her plait is more like something that will be done when people are in busy with studying or programming. Again, it looks very nice.
4. If you look further down, her jeans is kind of torn...again a symbol of real geeky, busy programmers.
5. The green sweater has an official as well as a soothing look.
Overall, people buying computer books will easily relate to her and thereby buying the HeadFirst Objects book.
Thanks.