Question: What is the birthdate of this English former footballer who played as a striker and who played for the 2012-13 Sheffield United F.C. season?
Sentence (from "David Wetherall"): David Wetherall (born 14 March 1971) is an English former footballer who played as a central defender, finishing his playing career with Bradford City at the end of the 2007–08 season.
Relevant evidence: No