Take a look at the item again:
As all of her classmates were sharing results
(A) Melody quietly left
the room (B)
and found a quiet corner in the hallway
(C) so that she could
see her grade without embarrassing herself in front of her friends.
You wanted to do this:
As all of her classmates were sharing results Melody quietly left the
room, and found a quiet corner in the hallway
so that she could see her grade without embarrassing herself in front of
her friends.
A comma after room is an error. And found a quiet corner in the hallway is a lonely verb phrase. When you connect such a phrase to the main clause in front, you do not use a comma.
You might want to review the rules.
Go back to the sentence to try again.