On November 10, 2020, Yongcheng Coal & Electricity Holding Group (skt*DRA) with AAA corporate credit rating claimed the default of its super short-term commercial paper (142 AS). It caused concerns of the marketparticipants and lowered prices of several similar bonds. 1. What is default? What is default risk? 2. What is the risk premium of a corporate bond? If investors believe that the default risk of a bond increases, what will happen to the risk premium? Please illustrate it with demand and supply curves. (you may illustate the supply and demand analysis verbally) 3. Why did the prices of similar bonds fall in response to the announcementof Yongcheng Coal & Electricity Holding Group? (Hint: consider the contagion effect)