Option 1 -> The shop specialized in antique books and first editions, not all varieties of books.
Option 2 -> While the passage mentions the shop was unique, this describes the shop's character, not why the author felt at home there.
Option 3 -> Physical proximity alone doesn't explain the emotional connection and comfort the author felt.
Option 4 -> The passage explicitly states "The shop was my sanctuary," indicating it was a safe haven where the author could escape daily life and read undisturbed.
Hence, Option 4: was his sanctuary -> The author directly calls the shop his sanctuary, describing it as an escape from "the daily ordeal of school" where he could spend entire days reading peacefully with his cat Tabby, largely undisturbed -> correct