Question

Joe's parents are sick __ his behaviour

Answer 1

I think it should be by.....

Answer 2

Answer :

This question is based on prepositions.

Cambridge English Dictionary defines 'preposition' as 'in grammar, a word that is used before a noun, a noun phrase, or a pronoun, connecting it to another word.'

'Of' is a preposition, which according to the Cambridge English Dictionary means 'used to show possession, belonging, or origin.'

So, the correct sentence is :

Joe's parents are sick of his behavior.