Bonjour Raghad !
The difference is the same as between "tu" and "vous" :
https://progress.lawlessfrench.com/revision/grammar/tu-and-vous-are-used-for-three-types-of-you
In the context of this specific question, you were given the hint: "Use the 'tu' form", which meant only "tes yeux" was correct there.
I hope that's helpful!
Bonne journée !