Question: Jack Stewart-Clark is the owner of what 15th-century castle?

Context paragraphs:
Kilmory Castle, Bute: Kilmory Castle (Kilmorie Castle, Crowner's Castle) is the remains of a 15th-century castle at Meikle Kilmory, Isle of Bute, Scotland.  The castle was the residence of the Jamiesons of Kilmorie, and was already a ruin in the 18th century.  The Jamiesons of Kilmorie were the hereditary coroners of Bute.  The ruins are a secular listed building.

Hayashi Castle: Hayashi castle was a 15th-century castle, (alternatively known as Hayashi-jo, Fukuyama-jo) in Satoyamabe village, Matsumoto city, Nagano, Japan.  A mountain-type castle, it is now largely in ruins.  The site is sometimes regarded as one castle, or two castles, Hayashikojo (the small castle) and Hayashiohjo (the larger castle).

Jack Stewart-Clark: Sir John "Jack" Stewart-Clark, 3rd Baronet (born 17 September 1929) is a British businessman and former Member of the European Parliament (MEP).  He represented the Conservative and Unionist Party in the European Parliament from 1979 until 1999.  He is the owner of Dundas Castle in West Lothian, Scotland.

Cathcart Castle: Cathcart Castle was a 15th-century castle, located in what is now Linn Park in the Cathcart area of southern Glasgow, Scotland.  The castle was abandoned in the 18th century, and the remaining ruins were pulled down in 1980, leaving only foundations visible.

Castle Sinclair Girnigoe: Castle Sinclair Girnigoe is located about 3 miles north of Wick on the east coast of Caithness, Scotland.  It is considered to be one of the earliest seats of Clan Sinclair.  It comprises the ruins of two castles: the 15th-century Castle Girnigoe; and the early 17th-century Castle Sinclair.

Dundas Castle: Dundas Castle is a 15th-century castle, with substantial 19th-century additions by William Burn, in the Dalmeny parish of West Lothian, Scotland.  The home of the Dundas family since the Middle Ages, it was sold in the late 19th century and is currently the residence of politician and businessman Sir Jack Stewart-Clark.

Audley's Castle: Audley's Castle is a 15th-century castle located 1 mile (1.6 km) north-east of Strangford, County Down, Northern Ireland, on a rocky height overlooking Strangford Lough.  It is a three-storey Tower house named after its 16th century owner, John Audley.  Audley's Castle tower house and bawn is a State Care Historic Monument in the townland of Castleward, in Down District Council area, at grid ref: J5781 5058.

Leskovec Castle: Leskovec Castle or Turn Castle (Slovene: "Grad Turn" , "Turn na Vrhu", "Turnska graščina", "Šrajbarski turn", "Grad Leskovec"; German: "Thurn am Hart" ) is a 15th-century castle north of the village of Leskovec pri Krškem (Municipality of Krško), southeastern Slovenia.  It has been redesigned in the 16th and the 18th centuries.

Crayke Castle: Crayke Castle is a grade I listed 15th-century castle in Crayke, North Yorkshire, England.  The castle consists of a restored 15th century four storey tower house with attached outbuildings to the rear and a separate ruined 15th tower, the "New Tower".  It is situated on Church Hill in the village of Crayke.

Het Oude Loo: Het Oude Loo (] ; The Old Woods) is a 15th-century castle on the estate of Het Loo Palace in Apeldoorn in the Netherlands.  The castle was built as a hunting lodge and is surrounded by a moat.  The castle is currently used by the Dutch Royal Family as a country house and guest residence.  It is not open for the public.

Supporting paragraphs: Jack Stewart-Clark Dundas Castle
Answer: Dundas Castle