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'.

Example Input: Lange was born in Cloquet, Minnesota, on April 20, 1949
Example Output: April 20, 1949

Example Input: Toni Collett was born on 1 November 1972, the eldest of three children; she has two younger brothers
Example Output: 1 November 1972

Example Input: Uma Karuna Thurman was born on April 29, 1970, in Boston, Massachusetts
Example Output:
April 29, 1970

