Question: Henry Fitzalan-Howard, Earl of Arundel was the eldest son of what Earl of Arundel between 1975 and 2002?
Context: Bernard Marmaduke Fitzalan-Howard, 16th Duke of Norfolk, (30 May 1908 – 31 January 1975), styled Earl of Arundel and Surrey until 1917, was a British peer and politician.  He was the eldest surviving son of Henry Fitzalan-Howard, 15th Duke of Norfolk, who died when Bernard was only 9 years old.  His mother was Gwendolen Fitzalan-Howard, "suo jure" Gwendoline Mary Herries, 12th Lady Herries of Terregles, and he inherited her peerage when she died in 1947. Edward William Fitzalan-Howard, 18th Duke of Norfolk, (born 2 December 1956), styled Earl of Arundel between 1975 and 2002, is a British peer, Earl Marshal and son of Miles Fitzalan-Howard, 17th Duke of Norfolk. Earl of Peterborough was a title in the Peerage of England.  It was created in 1628 for John Mordaunt, 5th Baron Mordaunt (see Baron Mordaunt for earlier history of the family).  He was succeeded by his eldest son, Henry, the second Earl.  He was a soldier and courtier.  Lord Peterborough had two daughters but no sons.  He was succeeded in the barony of Mordaunt (which could be passed through female lines) by his daughter, Mary, 7th Baroness.  The earldom was passed on to his nephew, Charles Mordaunt, 1st Earl of Monmouth (see below for earlier history of this branch of the family), who became the third Earl.  He was a prominent soldier and politician.  In 1705 he also succeeded his cousin Mary Mordaunt, 7th Baroness Mordaunt, in the barony of Mordaunt.  His eldest son John Mordaunt, Viscount Mordaunt, predeceased him, and Lord Peterborough was consequently succeeded by his grandson, Charles, the fourth Earl (the eldest son of Viscount Mordaunt).  The barony of Mordaunt (of the 1659 creation), the viscountcy of Mordaunt and the earldoms of Peterborough and Monmouth, became extinct on the death of the latter's son, the fifth Earl, in 1814.  The barony of Mordaunt was passed on to his half-sister, Lady Mary Anastasia Grace Mordaunt (see Baron Mordaunt for further history of this title). Henry Fitzalan-Howard, 15th Duke of Norfolk, (27 December 1847 – 11 February 1917), styled Baron Maltravers until 1856 and Earl of Arundel and Surrey between 1856 and 1860, was a British Unionist politician and philanthropist.  He served as Postmaster General between 1895 and 1900, but is best remembered for his philanthropic work, which concentrated on Roman Catholic causes and the city of Sheffield. Viscount Ullswater, of Campsea Ashe in the County of Suffolk, is a title in the Peerage of the United Kingdom.  It was created in 1921 for James Lowther upon his retirement as Speaker of the House of Commons.  He was the eldest son of the Hon. William Lowther, third son of the Hon. Henry Lowther, second son of William Lowther, 1st Earl of Lonsdale (see Earl of Lonsdale and Lowther Baronets for earlier history of the family).  The first Viscount lived to the age of 93, and was pre-deceased by both his eldest son the Hon. Christopher Lowther, a Conservative politician, and his eldest son's eldest son John Arthur Lowther (1910–1942) (who was Private Secretary to Prince George, Duke of Kent and was killed in the same air crash as him), the title being inherited by his seven-year-old great-grandson, the second and current Viscount, in an extremely rare instance of a great-grandson succeeding his great-grandfather in a peerage.  The second Viscount held office in the Conservative administrations of Margaret Thatcher and John Major and since 2003 he is one of the ninety elected hereditary peers that remain in the House of Lords after the passing of the House of Lords Act 1999.  As a descendant of the first Earl of Lonsdale he is also in remainder to this peerage and its subsidiary titles.  The current holder of the earldom, Hugh Lowther, 8th Earl of Lonsdale, is Lord Ullswater's fourth cousin. Gwendolen Mary Fitzalan-Howard, Duchess of Norfolk, 12th Lady Herries of Terregles (née Constable-Maxwell; 11 January 1877 – 28 August 1945) was the eldest child of Marmaduke Constable-Maxwell, 11th Lord Herries of Terregles and his wife, Angela (née Fitzalan-Howard).  On 5 February 1904, she married her first cousin once removed, the Henry Fitzalan-Howard, 15th Duke of Norfolk.  The couple later had four children: William d'Aubigny, 4th Earl of Arundel, also known as William de Albini V (b. 1203 – before 7 August 1224) was the eldest son of William d'Aubigny, 3rd Earl of Arundel and Mabel of Chester (born c. 1173), daughter of Hugh de Kevelioc, 3rd Earl of Chester and Bertrade de Montfort of Évreux.  He became Earl of Arundel and Earl of Sussex on 30 March 1221.  He was buried at Wymondham Abbey, Norfolk.  There is no evidence that he married or had children.  He was the Chief Butler of England and was succeeded by his brother, Hugh. Henry Miles Fitzalan-Howard, Earl of Arundel (born 3 December 1987 in London), is a British nobleman and racing driver.  He is the eldest son and heir of the 18th Duke of Norfolk and his wife Georgina.  He was known as Lord Maltravers from birth until his father's accession as Duke in 2002. Viscount FitzAlan of Derwent, of Derwent in the County of Derby, was a title in the Peerage of the United Kingdom.  It was created in 1921 for Lord Edmund Talbot on his appointment as Lord Lieutenant of Ireland.  Born Lord Edmund FitzAlan-Howard, he was the second son of Henry Fitzalan-Howard, 14th Duke of Norfolk.  In 1876 he assumed by Royal licence the surname of Talbot in lieu of his patronymic in an unsuccessful attempt to succeed to the estates of the Earl of Shrewsbury.  Shortly after being raised to the peerage he resumed the surnames of FitzAlan-Howard in lieu of Talbot.  The title became extinct on the death of his son, the second Viscount, in 1962. Baron Howard of Glossop, in the County of Derby, is a title in the Peerage of the United Kingdom, since 1975 a subsidiary title of the dukedom of Norfolk.  It was created in 1869 for the Liberal politician Lord Edward Howard, the second son of Henry Fitzalan-Howard, 13th Duke of Norfolk.  His grandson, the third Baron (who succeeded his father), married Mona Stapleton, 11th Baroness Beaumont.  Their eldest son, Miles, succeeded his mother in the barony of Beaumont in 1971 and his father in the barony of Howard of Glossop in 1972.  In 1975 he also succeeded in the dukedom of Norfolk on the death of his cousin, Bernard Fitzalan-Howard, 16th Duke of Norfolk.  The two baronies are now subsidiary titles of the dukedom of Norfolk.  See this title for further history of the peerages.
Answer: 18th Duke of Norfolk