Option 1: A description of Mahayana Buddhism - This option is incorrect. Patimokkha is not a description of Mahayana Buddhism. It is a term that specifically relates to the rules and regulations of the Sangha, the monastic community.
Option 2: A description of Hinayana Buddhism - This option is incorrect. Patimokkha is not a description of Hinayana Buddhism. It is a term used in relation to the rules and regulations of the Sangha, which is a common aspect in both Hinayana and Mahayana Buddhism.
Option 3: The rules of the Sangha - This option is correct. Patimokkha refers to the rules and regulations that govern the conduct of Buddhist monks and nuns in the Sangha. These rules cover various aspects of behavior, including ethics, discipline, and proper conduct.
Option 4: The questions of king Menander - This option is incorrect. Patimokkha is not related to the questions of king Menander. It is solely associated with the rules of the Sangha in Buddhism.
In summary, the correct answer is option 3, as Patimokkha stands for the rules of the Sangha in Buddhism.