The correct option is (b) When signs of organ degeneration appear
Explanation: In the first stage of syphilis, Chancre and rashes appear. Fever along with muscle and joints pain occur in the secondary stage. These symptoms also disappear. During the symptomless period which lasts for about 20 years, the bacteria may invade the body organs. When the signs of organ degeneration appear, the disease is said to be in a tertiary stage.