I would say the first would be usted and the second one would be nosotros
Hope this helps :)
1.
"le" is third person singular, so it goes with "el", "ella" or "usted".
A usted le gusta leer.
2.
"preferimos" is first person plural, so it goes with "nosotros" or "nosotras".
Nosotros preferimos leer.
