Question:
Which employer did Leslie Valiant work for in Dec, 1979?

Context:
 Leslie Valiant works for University of Edinburgh from Jan, 1976 to Jan, 1982. 
 Leslie Valiant works for Carnegie Mellon University from Jan, 1973 to Jan, 1974. 
 Leslie Valiant works for University of Leeds from Jan, 1974 to Jan, 1976. 
 Leslie Valiant works for Harvard University from Jan, 1982 to Jan, 1982.

Answer:
University of Edinburgh