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'.

Cameron Michelle Diaz was born August 30, 1972, in San Diego, California to Billie (nee Early), an import/export agent, and Emilio Diaz, a foreman of the California oil company Unocal
August 30, 1972