In the book Death Cloud by Andrew Lane what details did Sherlock use to eventually deduce that Virginia didn't write the letter inviting him to the fair?

answer choices
Virginia had told Sherlock that she hated him and would never speak to him again
The writing and paper looked like someone was trying to pretend to be a girl
The date and place noted in the letter were all wrong
The letter talked about things that Sherlock and Virginia had never discussed