Fill in the blank with the correct determiner:

Who is _______ girl sitting there?

The correct answer is 'the'.

Key Points

• A determiner is a word which is used at the beginning of a noun group to indicate, for example, which thing you are referring to or whether you are referring to one thing or several.
• 'A/an' and 'the' are articles. They are a type of determiner and they go before a noun.
• A/an before a noun shows that what is referred to is not already known to the speaker, listener, writer and/or reader (it is the indefinite article).
  • Example - Do you have a car?
• 'The' before a noun shows that what is referred to is already known to the speaker, listener, writer and/or reader (it is the definite article) or it is used when we talk about a particular person or thing or one already referred to (that is, when it is clear from the context which one we mean).
  • Example - The book you want is out of print.
• In the given sentence, the determiner 'the' is used to point the particular girl that is sitting there.
• Thus, the correct determiner to fill in the blank is 'the'.

Hence, the correct answer is option (4).