The following sentence has been split into four segments. Identify the segment that contains a grammatical error.
You know that I am fond of reading / and also that all books are my favourite / but you don’t know that this is one of / my favourite book.

Correct option is C

The grammatical error lies in the segment: (c) my favourite book.
Explanation:
The error is in subject-verb agreement and noun form related to the phrase "one of".
· The construction "one of" must always be followed by a plural noun, because you're referring to one item out of many.
· In this case, the sentence says:
· "this is one of my favourite book", which is incorrect because "book" is singular.
Grammar/Usage Rule:
· Use plural nouns after expressions like:
· one of the + plural noun
· some of the + plural noun
· Examples:
· She is one of my best friends.
· This is one of the most exciting games I've played.
Correct phrase:
"my favourite books" (plural form)