Select the most appropriate option to fill in the blank.

Recycling is a key component of modern waste reduction and is the third component of the ‘Reduce, Reuse and Recycle’ waste hierarchy _______ aim is to extract the maximum practical benefits from products and to generate the minimum amount of waste.

The correct answer is 'whose'.

Key Points

• The most appropriate word for the given blank is 'whose'.
• The word "whose" is a pronoun used to show possession.
• In this sentence, the "waste hierarchy" possesses the aim of extracting maximum practical benefits from products and generating the minimum amount of waste.
• The other options are not appropriate because "who's" is a contraction of "who is" or "who has," "which" is used to refer to things or animals, and "whom" is used as the object of a verb or preposition.
• Therefore, "whose" is the most appropriate word to use here. 
   

Correct Sentence: Recycling is a key component of modern waste reduction and is the third component of the ‘Reduce, Reuse and Recycle’ waste hierarchy whose aim is to extract the maximum practical benefits from products and to generate the minimum amount of waste.