"Do they want a shirt?"
Translation:¿Quieren ellos una camisa?
Hmm I didn't see camiseta in my choices but it just means t-shirt. Desean is from the word desear (to want, wish) according to my online search. It's been years since I took spanish but it sounds familiar. I don't know how many possible choices are programmed in Duolingo but desean didn't come up for me.