This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
Which of the following is known as eighth day disease? 
Select and explain. 
A. Puerperal tetanus, B. Tetanus neonatorum, C. Varicella, D. Measles
B: Tetanus neonatorum
Answer: B: Tetanus neonatorum 
Explanation: Tetanus neonatorum is known as eighth day disease. The common cause of neonatal tetanus is infection of umbilical stump and signs usually appear about the 7th day. Ref: Park 21st edition, page 286.