"This is Abraham's and Sarah's boy."

Translation: זה הילד של אברהם ושרה.

[Heysoos1]

Guys, so I put in this answer based on classical Hebrew, and didn't expect it to be right.
זה ילד אשר לאברהם ולשרה
But it said "almost right!" And highlighted everything except זה.
Is what I wrote correct/understandable?

[Pumbush]

It doesn't work at all in modern Hebrew, No "the", אשר is also weird there.

[Heysoos1]

Yeah that's what I thought. Even classical Hebrew, I thought I got that totally wrong. I reported it.

[Avabelieve]

In English it should be "Abraham & Sarah's"

[Heysoos1]

Um... no? Either is right.