Given a short bio of a person, find the minimal text span containing the date of birth of the person. The output must be the minimal text span that contains the birth date, month and year as long as they are present. For instance, given a bio like 'I was born on 27th of Decemeber 1990, and graduated high school on 23rd October 2008.' the output should be '27th of December 1990'.

[EX Q]: Edward John David Redmayne was born on 6 January 1982 in Westminster in London
[EX A]: 6 January 1982

[EX Q]: Mortensen was born in Watertown, New York, on October 20, 1958, the son of Grace Gamble (née Atkinson; July 8, 1928 – April 25, 2015) and Viggo Peter Mortensen Sr
[EX A]: October 20, 1958

[EX Q]: Walter Bruce Willis was born in Idar-Oberstein, West Germany, on March 19, 1955
[EX A]:
March 19, 1955