Alan Turing’s mother, Ethel Sara Turing, had the maiden surname Stoney.
Ethel was born into the Stoney family and was the daughter of Edward Waller Stoney, who served as chief engineer of the Madras Railways. The family had Anglo-Irish Protestant roots connected with counties Tipperary and Longford, while Ethel spent much of her childhood in County Clare.
She married Julius Mathison Turing on 1 October 1907. Alan was their second son, born in London in 1912, and his upbringing was shaped partly by the expectations and social conventions of a British family serving in India. His father worked in the Indian Civil Service, while Ethel managed family life during periods when the household was divided between India and Britain.
The other options refer to people or ideas associated with Turing’s story, but none is his mother’s family name. “Stoney” is the surname before Ethel’s marriage, not a nickname or a name connected to Alan’s scientific work.