"They are yours" was not accepted - since there is no context, surely that should be counted as correct too?
There's a mismatch in number. "They are yours" would be "Sono tuoi" or "Sono tue".
"Sono tue" is exactly what I heard. I think this is a poor sentence for a computer voice to read aloud. The difference is hard to make out, and is critical.
Can anyone tell me why it uses tua instead of tuo?
Can another translation be "It is yours" ??
No. "sono" is first person singular ("I am") or third person plural ("they are"). It can't be "they are yours" either because "tua" is singular.