Right choice is (a) Colin Maclaurin
To explain: Colin Maclaurin (February 1698 – 14 June 1746), was a Scottish Mathematician. The Maclaurin Series was named after him.
Normand Maclaurin (10 December 1835 – 24 August 1914) was a Scottish-born physician, company director, Australian politician and university administrator.
Ian Maclaurin, born 30 March 1937, is a British businessman, who has been chairman of Vodafone and chairman and chief executive of Tesco.
Richard Cockburn Maclaurin (June 5, 1870 – January 15, 1920) was a Scottish-born U.S. educator and mathematical physicist.