Explanation

Asad Durrani is the correct answer because he has been reported to have co-authored a book with a former RAW chief. M. Riaz is incorrect as there is no widely known record of him co-authoring such a book. Hameed Gul is incorrect because his association with co-authoring a book with a former RAW chief is not the established fact here. Nadeem Taj is incorrect as he is not cited for this specific collaboration.