Greg Penner
Gregory B. Penner( born December 18, 1969) is an American businessman and venture capitalist.
Penner was named the chairman of Walmart on June 5, 2015.
He is the son-in- law of S. Robson Walton and the grandson- in- law of Sam Walton, the founder of Walmart.
Wyndham Goold
Wyndham Goold( 1812-1854) was a Member of Parliament( MP) for County Limerick from 1850 to 1854.
Goold was educated at Westminster School and Trinity College, Dublin.
He was the son in law of Frederick Falkiner Goold, Archdeacon of Raphoe and brother in law of Bishop Hamilton Verschoyle
Gertrude Maseko
Gertrude Hendrina Maseko is the incumbent First Lady of Malawi.
She married President Peter Mutharika on 21 June 2014.
Maseko originates from the village of Kapasule in Balaka District.
She was a member of the National Assembly for the DPP between 2009 and 2014, having been elected in the 2009 general elections.
Hypatius (consul 359)
Flavius Hypatius( c. 340- died after AD 383) was a Roman Senator, who was the brother- in- law of the Roman emperor Constantius II.
Robert W. Levering
Robert Woodrow Levering( October 3, 1914 – August 11, 1989) was a U.S. Representative from Ohio, son-in- law of Usher L. Burdick and brother- in- law of Quentin N. Burdick.
Nick Sidi
Nick Sidi( born 22 February 1966 in Manchester, England) is an English actor.
He is the son -in- law of actress Rosalind Knight and brother- in- law of actress Susannah Elliott- Knight.
He often plays drama or comedy roles on television and frequently appears in BBC dramas.
Charles Francis Norton
Charles Francis Norton( 1807 – 1835) was a 19th- century Member of Parliament for Guildford.
Norton was also a Captain of 52nd Light Infantry; son-in- law of Sir Colin Campbell; brother- in- law of writer Caroline Norton
Robert Vadra
Robert Vadra is an Indian businessman, entrepreneur and the husband of Priyanka Gandhi.
He is the son -in- law of Sonia Gandhi and Rajiv Gandhi, and the brother- in- law of Rahul Gandhi.
Eusebius (consul 359)
Flavius Eusebius( died after AD 371) was a Roman Senator, who was the brother- in- law of the emperor Constantius II.
Peter Mutharika
Arthur Peter Mutharika (born 18 July 1940) is a Malawian politician, educator and lawyer who has been President of Malawi since 31 May 2014.
Mutharika has worked globally in the field of international justice.
He is an expert on international economic law, international law and comparative constitutional law.
He informally served as an adviser to his older brother, President Bingu wa Mutharika, on issues of foreign and domestic policy from the onset of his election campaign until the President's death on 5 April 2012.
He has also held positions as Minister of Justice and later as Minister for Education, Science and Technology.
Mutharika also served as Minister of Foreign Affairs from 2011 to 2012.
He was charged to help bridge relations between Malawi and the United Kingdom due to the deterioration of public diplomacy between the two nations after the Cochrane-Dyet controversy.
Standing as the candidate of the Democratic Progressive Party (DPP), Peter Mutharika was elected as President of Malawi in the 2014 election.

Question: Who is the sibling-in-law of Gertrude Maseko?
Answer: Bingu wa Mutharika