Customers: John Doe (DOB:1/5/1940)Jane Doe (DOB:4/15/1945)Jimmy Doe (DOB:7/15/1970)Oldest customer's birthdate: 1/5/1940Youngest customer's birthdate: 7/15/1970
XmlTextWriter Output: <Date>2021-01-19T00:00:00.0000000-05:00</Date>