There are students in a class who don't leave names for good deeds. A. B, C, D, and other teachers expressed their views on the 4 students in the class. A said: "If this is not done by Zhang San, it must be Zhao Liu did. "B said," If Zhang San did this, then Li Si or Wang Wu would do it. "C said," If Li Si did not do this, Wang Wu would not do it. Zhao Liu will not be the one who does it. "Ding said," This thing must be done by Zhang San, and neither Li Si nor Wang Wu will do it. ". It was learned afterward that only one of the four teachers' views was correct. Based on this, who can launch a good deed? ['Zhang San.', 'Lee Si.', 'Wang Wu.', 'Zhao Liu.']