I think is the third one, because in the giving sentence it says: I don’t like doing sports, so I think the third one fit in for that.
*Los mandatos informales
-"Escribe (tu) la tarea"
-"Compra (tu) los libros"
*Los mandatos formales
-"Haga (Usted) la tarea"
-"Compren (Ustedes) los libros"
