He hovered over the words and "trinkt aus" says it means "finish". So translating it directly would be "she finishes the glass." If "trinkt aus" does not mean finish then this should be corrected. If it does, then "She finishes the glass" should also be an acceptable answer. Either way there is apparently an error.
I checked Wordreference which says that austrinken can mean to drink up. The sentence could therefore be She drinks the glass up or She finishes the glass, so sorry I suggested that it would be entirely wrong. However, I don't think many people would just write "she finishes the glass" - usually you say the glass of something if you're using that expression to mean that they drank every last drop: She drank the glass of milk all up.
In that case the verb should become trinken http://german.about.com/library/weekly/aa100200a.htm
No se dice drink outside of the glass sino drink out of the glass. Aunque en ciertas circunstancias out y outside significan fuera, en este contexto out se traduce a "de" en español: bebe del vaso = he drinks out of the glass. Esto es probablemente porque el agua mueve de dentro del vaso AFUERA (a tu boca).