Question:
Who was the head of state of German Democratic Republic in May, 1980?

Context:
 Egon Krenz is the head of the state of German Democratic Republic from Oct, 1989 to Dec, 1989. 
 Willi Stoph is the head of the state of German Democratic Republic from Oct, 1973 to Oct, 1976. 
 Erich Honecker is the head of the state of German Democratic Republic from Oct, 1976 to Oct, 1989. 
 Wilhelm Pieck is the head of the state of German Democratic Republic from Oct, 1949 to Sep, 1960. 
 Walter Ulbricht is the head of the state of German Democratic Republic from Sep, 1960 to Aug, 1973. 
 Manfred Gerlach is the head of the state of German Democratic Republic from Dec, 1989 to Apr, 1990. 
 Sabine Bergmann-Pohl is the head of the state of German Democratic Republic from Apr, 1990 to Oct, 1990.

Answer:
Erich Honecker