Question:
Which position did Xavier de La Chevalerie hold in Dec, 1984?

Context:
 Xavier de La Chevalerie holds the position of ambassador of France to Japan from Jan, 1979 to Jan, 1982. 
 Xavier de La Chevalerie holds the position of ambassador of France to the Holy See from Jan, 1983 to Jan, 1985. 
 Xavier de La Chevalerie holds the position of ambassador of France to Mexico from Jan, 1970 to Jan, 1973. 
 Xavier de La Chevalerie holds the position of ambassador of France to Senegal from Jan, 1973 to Jan, 1977. 
 Xavier de La Chevalerie holds the position of ambassador of France to Canada from Jan, 1977 to Jan, 1979.

Answer:
ambassador of France to the Holy See