Why not "मैं प्यासा हूँ।"
Both are correct.
Your sentence is appropriate if you're male. However the given sentence is for a female speaker. Duolingo should be more specific here.
How can you say ' The speaker of I am thirsty is a female' ? Translation from English to Hindi!
You are correct sir
it is obvious that the word pyaSI is feminine...
NOT ALL but most words in hindi that end with the SOUND of "e" are feminine...