Clarence House has been the official residence of the heir apparent of who?
Queen Elizabeth II
Title: Charles, Prince of Wales
Passage: Charles, Prince of Wales (Charles Philip Arthur George; born 14 November 1948) is the eldest child and heir apparent of Queen Elizabeth II.  Known alternatively in Cornwall as Duke of Cornwall and in Scotland as Duke of Rothesay, he is the longest-serving heir apparent in British history, having held the position since 1952.  He is also the oldest person to be next in line to the throne since Sophia of Hanover (the heir presumptive to Queen Anne), who died in 1714 at the age of 83.
Title: Clarence House
Passage: Clarence House is a royal residence in London, situated on The Mall, in the City of Westminster.  It is attached to St. James's Palace and shares the palace's garden.  For nearly 50 years, from 1953 to 2002, it was home to Queen Elizabeth The Queen Mother.  It has since been the official residence of Charles, Prince of Wales, and Camilla, Duchess of Cornwall.
Title: List of heirs to the Prussian throne
Passage: This is a list of those people who were heir apparent or heir presumptive to the Kingdom of Prussia from its foundation in 1701 to the end of the monarchy in 1918.  From 18 January 1871 the Crown Prince of Prussia was also heir apparent to the German Empire.  Those heirs who succeeded are shown in bold.
Charles, Prince of Wales Clarence House