"La niña está muy feliz."
Translation:The girl is very happy.
What is 'lass' as it showed in the correct answer (translation) as "The lass is very happy."
Lass = girl. Lad = boy. Not common in US. More common in Ireland and UK, I think.
feliz is an adjective right? So it should get modified as per the gender. For "busy" = occupado or occupada