Demonstratives, this, that, these and those, are used to point to people and things. They are used as determiners and pronouns.

https://learnenglish.britishcouncil.org/en/english-grammar/pronouns/that-these-and-those http://dictionary.cambridge.org/grammar/british-grammar/determiners/this-that-these-those

Determiners are words which come at the beginning of the noun phrase.

• referring determiners
  • articles
  • demonstratives
  • possessives, possessive 's
• quantifying determiners
  • quantifiers
  • numerals
• interrogatives: whose, which, what

Two referring determiners can't be used together.

https://learnenglish.britishcouncil.org/en/english-grammar/determiners-and-quantifiers http://dictionary.cambridge.org/grammar/british-grammar/determiners http://dictionary.cambridge.org/grammar/british-grammar/determiners-the-my-some-this https://en.oxforddictionaries.com/grammar/determiners

Interrogative pronouns are used to ask questions.

• who: as a subject/an object, as a pronoun
• which: as a subject/an object, as a pronoun/determiner
• whom: as an object(formal), as a pronoun
• what: as a subject/an object, as a pronoun/determiner
• whose: as a subject/an object, as a pronoun/determiner

http://dictionary.cambridge.org/grammar/british-grammar/pronouns/questions-interrogative-pronouns-what-who https://learnenglish.britishcouncil.org/en/english-grammar/determiners-and-quantifiers/interrogative-determiners-which-and-what