Hi, Asli.
In those sentences you can only use "que' and not "quien" because they are defining relative clauses. If they were non-defining relative clauses, you could use both 'que' and 'quien', but with defining relative clauses, you can only use 'que'. Some examples:
Esa es la chica que trabaja en el supermercado (That's the girl who works in the supermarket)
and NOT *Esa es la chica quien trabaja en el supermercado <- NOT
Juan es el mejor amigo que he tenido (Juan is the best friend I have had)
and NOT *Juan es el mejor amigo quien he tenido <- NOT
Here some examples with non-defining relative clauses, where you can use both 'que' and 'quien':
Ayer comí con mis padres, que tienen un coche nuevo / Ayer comí con mis padres, quienes tienen un coche nuevo (Yesterday I ate with my parents, who have a new car)
Este es Juan, que trabaja en un hospital / Este es Juan, quien trabaja en un hospital (This is Juan, who works in a hospital)
However, if there is a preposition before the relative pronoun, you can use 'quien' even if it's a defining relative clause. I'm sorry but languages have this kind of tricky stuff. So you can say:
Ese es el chico de quien he oído hablar mucho (That's the boy I have heard a lot about)
María es una persona en quien puedes confiar (María is a person you can trust in)
I hope I helped you a little.