Option 1 -> "Slavering over" suggests spending considerable time with the books, which implies careful examination of each restored edition.
Option 2 -> The word "slaver" (to drool) metaphorically conveys intense desire and admiration, matching the narrator's description of being "completely charmed" and finding everything "desirable."
Option 3 -> "Slavering" indicates intense interest, not disinterest - contradicts the narrator's enchanted reaction to the bookshop.
Option 4 -> The narrator admires the restoration work and Rao's "meticulous care," showing appreciation rather than frustration.
Hence, Options 1 and 2 -> "Slavering over the books" captures both the physical act of carefully examining each restored book and the emotional state of being overwhelmed with admiration for them - the phrase conveys the narrator's complete absorption in both inspecting and coveting Rao's carefully restored collection -> correct