Why not "why does she study Spanish?"
That's good too.
And yet, still, they rejected both "why does she study spanish" and "why is she studying spanish". And they don't show study or studying as alternate translations in the drop-down.
I also used 'studying' and was marked wrong. Clearly there is no native English consultant. And, yes, I reported it.
I also used "studying" and was marked wrong!
...because it's the de facto second official language of her home state, California! Obviously :)