Triple

Target entity: Four-Year Sejm (Great Sejm)
Context triple: [Poland’s Constitution Day, relatedEvent, Four-Year Sejm (Great Sejm)]

• A. Sejm of the Kingdom of Poland
  The Sejm of the Kingdom of Poland was the bicameral parliament of Congress Poland, functioning as a representative legislative body under the political framework established after the Congress of Vienna.
• B. Sejm of the Polish–Lithuanian Commonwealth chosen
  The Sejm of the Polish–Lithuanian Commonwealth was the bicameral parliament of the federated Polish and Lithuanian states, serving as a central legislative and political institution from the 15th to the late 18th century.
• C. Sejm of the Second Polish Republic
  The Sejm of the Second Polish Republic was the unicameral parliament of interwar Poland, serving as the central legislative body of the state from its post–World War I independence until the outbreak of World War II.
• D. Sejm of the Polish People's Republic
  The Sejm of the Polish People's Republic was the unicameral legislature of communist-era Poland, functioning as a nominal parliament under the control of the ruling Polish United Workers' Party.
• E. Sejm of Central Lithuania
  The Sejm of Central Lithuania was the short-lived unicameral parliament of the Republic of Central Lithuania, elected in 1922 and chiefly known for voting in favor of that state's incorporation into Poland.
• F. None of above.
• G. Unsure - the case is ambiguous/there is not enough information to decide.