What Did Sociologist Georg Simmel Describe with His Concept "Neurasthenia

What did sociologist Georg Simmel describe with his concept "neurasthenia"?

A) A psychological condition, similar to multiple personality disorder, where the individual feels torn between their home life and their work life in the city, and begins to live two nearly separate lives.
B) A neurotic sense of anxiety and stress which is arguably inherent to an urban way of life.
C) A respiratory condition that is caused by overexposure to urban environmental conditions, such as increased smog and noise pollution.
D) The postmodern obsession with global warming, climate change, and environmental deterioration.
E) None of the above