Question: Who is Lord Richard Cavendish (1752–1781)'s paternal grandmother?
Sentence (from "William Cavendish, 4th Duke of Devonshire"): William Cavendish, 4th Duke of Devonshire, (8 May 1720 – 2 October 1764), styled Lord Cavendish before 1729 and Marquess of Hartington between 1729 and 1755, was a British Whig statesman and nobleman who was briefly nominal Prime Minister of Great Britain.
Relevant evidence: No