A、2011. B、2012. C、2013. D、2014. C短文提到该案发生于2013年3月31日。由此可知，这个案件发生在2013年，故选C。

China’s Supreme People’s Court (SPC) on Wednesday approved the death sentence for (19) a postgraduate student charged with poisoning his roommate after reexamining the victim’s cause of death. (19) Lin Senhao, a student at Shanghai’s prestigious Fudan University, used N-Nitrosodimethylamine, a chemical compound taken from a university lab, (20) to contaminate a water dispenser in his dormitory on March 31, 2013. Prosecutors argued that Huang Yang, his roommate, drunk the tainted water and this caused him to die of organ failure on April 16.
    Huang’s father told Beijing-based The Mirror newspaper that "I support the court’s decision and I’m glad my son has gotten justice." Lin Zunyao, Lin’s father, told the West China City Daily on Wednesday that "after I received notice (of the death sentence), I did not slept for the whole night. " "There are lots of questions about the case," he added.
    In June, Lin’s lawyer Xie Tongxiang claimed that Huang might have died from an allergic reaction to a drug. Xie submitted seven application letters to the SPC, requesting a reexamination of the victim’s cause of death.
    "If Huang died of poison, why were no metabolic substances related to the chemical compound found in his system? Several liver disease and forensic experts have said that Huang’s symptoms did not correspond with the poison, but were consistent with drug-induced hepatic disease, drug allergies or acute viral hepatitis B," Xie claimed in a letter. (21) The Shanghai No. 2 Intermediate People’s Court convicted Lin of intentional homicide in the first trial and sentenced him to death in February 2014.
19. What do we know about Lin Senhao?
20. When did this homicide case happen?
21. What judgement did Lin Senhao receive from the court?