Question: The Old Tullamore Distillery was the original home of a whiskey produced by what company?

Context paragraphs:
Elijah Craig (bourbon): Elijah Craig is a premium brand of bourbon whiskey produced by the Heaven Hill Distillery company.  The company is headquartered in Bardstown, Kentucky, and its distillery (called the Heaven Hill Bernheim distillery) is in Louisville, Kentucky.  The brand is sold as a straight bourbon.  It is sold in glass 750ml bottles, and the Small Batch bourbon is also available in glass 1.75L bottles.

Tullamore Distillery: The Tullamore Distillery is an Irish whiskey distillery built by William Grant & Sons in Tullamore, County Offaly, Ireland, in 2014.  It is the first new distillery to have been constructed on a greenfield site in Ireland in over 100 years, and the first to operate in Tullamore since 1954.

Jones Road Distillery: The Dublin Whiskey Distillery Company Jones Road Distillery also known as the D.W.D. Distillery, Jones Road, or just Jones Road Distillery, was one of the six great Irish whiskey distilleries of Dublin city visited and documented by Alfred Barnard in his seminal 1887 publication "The Whisky Distilleries of the United Kingdom".  It was located on the north side of the city on the banks of the river Tolka, approximately a mile north of the city centre.  The distillery was built by the Dublin Whiskey Distillery Company Ltd and the Irish whiskey produced sold around the world under the brand name D.W.D.

Buffalo Trace Distillery: Buffalo Trace Distillery is a distillery located in Frankfort, Kentucky.  It has historically been known by several names, including most notably, the George T. Stagg Distillery and the O.F.C. Distillery.  Its namesake bourbon brand, "Buffalo Trace" Kentucky Straight Bourbon whiskey, was introduced in August 1999.  The company claims the distillery is the oldest continuously-operating distillery in the United States.  Located on what the company claims was once an ancient buffalo crossing on the banks of the Kentucky River in Franklin County, the distillery is named after the American bison.  The Sazerac Company, an American family-owned producer and importer based in New Orleans, Louisiana, purchased the distillery in 1992 and is now the parent company of Buffalo Trace Distillery.

Knappogue Castle Irish Whiskey: Knappogue Castle Irish Whiskey is a brand of premium single malt Irish whiskey produced by Castle Brands Inc.  It is one of the few independent bottlings of Irish whiskey currently available on the market.  The brand is named for historic Knappogue Castle in County Clare, Ireland, originally built by Clan MacNamara in 1467.  Knappogue Castle is known for bottling one of the oldest and rarest known Irish whiskies, Knappogue Castle 1951, a pot still whiskey produced at the now-defunct B. Daly Distillery.

Old Tullamore Distillery: The Old Tullamore Distillery was an Irish whiskey distillery which was established in Tullamore, County Offaly, Ireland, in 1829.  The original home of Tullamore Dew Irish whiskey, the distillery closed in 1954, having endured financial difficulties for many years, like many Irish whiskey distilleries of the early 20th century.

Marrowbone Lane Distillery: The Marrowbone Lane Distillery was an Irish whiskey distillery located on Marrowbone Lane, in Dublin, Ireland.  One of the "big four" historical Dublin whiskey firms, it was run by William Jameson, a member of the Jameson whiskey dynasty.  However, the whiskey now known as Jameson Irish Whiskey was not produced at this distillery, but at the separate enterprise run by John Jameson at the nearby Bow Street Distillery.  The distillery closed in 1923 following financial difficulties.

Kentucky Tavern: Kentucky Tavern is a brand of straight bourbon whiskey produced by the Sazerac Company at the Barton Distillery located in Bardstown, Kentucky, who acquired the brand from United Distillers in 1995.  The brand was originally produced and owned by the R. Monarch Distillery (RD #24, 2nd Dist.)  of Owensboro, Kentucky, which entered bankruptcy in 1898 and was purchased by James Thompson in 1901 who renamed the company Glenmore Distillery Company with locations in Owensboro and Louisville, Kentucky.  In 1903 The Kentucky Tavern trademark was first registered.  Glenmore proved a successful and durable company, its main brand being Kentucky Tavern.  It is usually produced as an 80 proof liquor, although a 100 proof is also available.

1792 Whiskey: 1792 Whiskey is a Kentucky straight Bourbon whiskey produced by the Barton 1792 Distillery in Bardstown, Kentucky.  The brand and distillery are owned by the Sazerac Company.  It is part of a line of small-batch bourbons aimed at the high-end liquor market.

Tullamore Dew: Tullamore Dew is a brand of blended Irish whiskey produced by William Grant & Sons.  It is the second largest selling brand of Irish whiskey globally, with sales of over 950,000 cases per annum as of 2015.

Supporting paragraphs: Old Tullamore Distillery Tullamore Dew
Answer: William Grant & Sons