Question:
Which position did Jan Kappeyne van de Coppello hold in Sep, 1878?

Context:
 Jan Kappeyne van de Coppello holds the position of Prime Minister of the Netherlands from Nov, 1877 to Aug, 1879. 
 Jan Kappeyne van de Coppello holds the position of Minister of the Interior and Kingdom Relations from Nov, 1877 to Aug, 1879. 
 Jan Kappeyne van de Coppello holds the position of member of the Senate of the Netherlands from May, 1888 to Sep, 1893. 
 Jan Kappeyne van de Coppello holds the position of member of the House of Representatives of the Netherlands from Sep, 1871 to Nov, 1877. 
 Jan Kappeyne van de Coppello holds the position of municipal councillor of The Hague from Sep, 1859 to Sep, 1865.

Answer:
Prime Minister of the Netherlands