Which State do I File?

We live in CO, our dependent daughter (20) attends an out of state school (CA) and worked part time, making less than is required to file state taxes.  She also received a 1098-T from a CA school and a 1099-Q. (All of the 529 distributions were for qualified education expenses, so she does not owe tax on these.)
Which State taxes does she need to file?   CO or CA?  
Thanks in advance.