Option 1 -> Starts with "William Ury" before establishing context - incorrect sentence structure.
Option 2 -> Begins with the main action "recently I spent several hours sitting," then adds location and introduces the person with appositive details - flows naturally.
Option 3 -> Places "William Ury" immediately after "sitting" which breaks the logical flow of the action.
Option 4 -> Starts with a relative clause "who specialises" without an antecedent - grammatically impossible.
Hence, Option 2: (B), (D), (A), (C) -> The sentence correctly reads: "Recently I spent several hours sitting under a tree in my garden with the social anthropologist, William Ury, a Harvard University professor who specialises in the art of negotiation and wrote the best-selling book, Getting to Yes." This follows proper English syntax: main clause → prepositional phrase → appositive identification → relative clause. -> correct