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'.

On 19 August 1946, Ti was born as Tam Fu Wing (譚富榮) in Xinhui, Guangdong Province, China into a family with 4 members including himself, his parents and a younger sister
On 19 August 1946
The text span 'On 19 August 1946' is the minimal text that contains the date of birth of Tam Fu Wing..