Quién or Qué?

Quién or Qué?
 

Following problem: mi profesora de español asked me to write sth on the following subject: Quién es Cristiano Ronaldo? In your opinion, does that mean you can use ¿Quién? to ask for sth besides your name? Or is the question intended to cause confusion and the only possible assumption is here that the sentence should start with Qué?

¿Quién es...? and ¿Qué es ...? generally have distinct meanings and require different answers.

¿Quién es Cristiano Ronaldo? typically asks for an identification. You are at a party, you know that one of the people there is Cristiano Ronaldo, but you have never met Cristiano before and you don't know what he looks like. If you want your friend to point him out, you must ask ¿Quién es ...?

¿Qué es Cristiano Ronaldo? typically asks for a definition. Same party, but you want to know what role Cristiano Ronaldo fills in society: parent? doctor? laborer? If you want your friend to tell you about him, you must ask ¿Qué es ...?

I agree with Wrholt.
Also, "¿quién es?" is not only asking for a physical identification, but for someone's characteristics that make them be who they are.

--¿Quién es Miguel de Cervantes?
--Es un escritor español del Siglo de Oro; es el autor de El Quijote.

--¿Qué es Miguel de Cervantes?
--Es escritor.


--¿Quién es Ricky Martin?
--Es el cantante puertorriqueño que se presentó en la clausura del Mundial de Futbol en Francia.

--¿Qué es Ricky Martin?
--Es cantante.