Question:
Which employer did Hua Luogeng work for in Jan, 1959?

Context:
 Hua Luogeng works for University of Illinois at Urbana–Champaign from Jan, 1948 to Jan, 1950. 
 Hua Luogeng works for Tsinghua University from Jan, 1950 to Jan, 1965. 
 Hua Luogeng works for Yunnan University from Jan, 1938 to Jan, 1945. 
 Hua Luogeng works for Institute for Advanced Study from Jan, 1946 to Jan, 1948.

Answer:
Tsinghua University