The correct answer is (a) Russia.
Nihilism is a philosophy that rejects all traditional values and beliefs. It originated in Russia in the 19th century, and was influenced by the work of philosophers such as Friedrich Nietzsche and Max Stirner. Nihilists believe that there is no objective meaning or purpose to life, and that all values are relative. They often advocate for radical social change, and have been associated with terrorism and other forms of violence.
The other options are incorrect. America, China, and Mongolia are all countries where nihilism has been present, but it did not originate in any of these countries.