I've been thinking so hard over this for a good 15 minutes. Would like to know which makes sense?

...the Member State which the asylum seeker first enters European Union (EU) is responsible for processing the asylum claim. 

...the Member State which the asylum seeker first enters European Union (EU) through is responsible for processing the asylum claim. 

... the Member State which the asylum seeker first enters European Union (EU) from is responsible for… 

Thanks a lot!