You will be given a context, a subject and a relation. Your task is to generate a question based on the subject and relation. The generated question should include the given subject. Try to use a minimum number of words that are not present in either context, subject or relation while generating question.

Context : The BBC adapted The Warden and its sequel, Barchester Towers, into the miniseries The Barchester Chronicles (1982). 
Subject : The Warden 
Relation : series
To which series does The Warden belong?

Context : The Immortal Game was a chess game played by Adolf Anderssen and Lionel Kieseritzky on 21 June 1851 in London, during a break of the first international tournament. 
Subject : Immortal Game 
Relation : point in time
When did Immortal Game occurr?

Context : Elections to the European Parliament were held in Belgium on June 10, 1979. 
Subject : Elections to the European Parliament 
Relation : point in time

On what date did Elections to the European Parliament occur?