There are three interrogative pronouns qui, que and lequel in French that can be used to ask questions using both subject-verb inversion (if que is an object, not the subject) and est-ce que. We also include the word quoi which is simply the form of que used after prepositions.

Qui is used for people and translates as “who”or “whom”:

   Avec qui aimeriez-vous parler?
   With whom would you like to speak?

Que is used for objects or ideas when the question is not asking about an option among choices - the interrogative adjective quel is used for that:

   Qu'est-ce qu'il veut?
   What is it that he wants?

After a preposition que changes to quoi in a similar way to disjunctive pronouns:

   En quoi pense-elle?
   What is she thinking about?

Lequel translates best as “which one” and is a special case in that it can only refer to objects already discussed:

   Quel film veux-tu regarder? Lequel veux-tu regarder?
   Which movie do you want to watch? Which one do you want to watch?

It is essentially a combination of the definite le pronoun and the word quel, and like those it changes based on gender and plurality:

	Masculine	Feminine
Singular	lequel	laquelle
Plural	lesquels	lesquelles

And, because it uses definite articles, it can also form contractions with the prepositions à and de:

   Duquel parles-tu?
   Which one are you thinking about?

   Lequel allez-vous?
   Which one are you going to?