Read this and answer the question. If the question is unanswerable, say "unanswerable".

The Netherlands regained independence from France in 1813. In the Anglo-Dutch Treaty of 1814 the names "United Provinces of the Netherlands" and "United Netherlands" were used. In 1815 it was rejoined with the Austrian Netherlands, Luxembourg and Liège (the "Southern provinces") to become the Kingdom of the Netherlands, informally known as the Kingdom of the United Netherlands, to create a strong buffer state north of France. After Belgium and Luxembourg became independent, the state became unequivocally known as the Kingdom of the Netherlands, as it remains today.

What happened to the Kingdom of the United Netherlands after France became independent?
unanswerable