MONTCLAIR, VA. — It was once Oldies as “XTRA 104” and after that was “Z104” in an era of the Spice Girls and TLC. Now, WPRS-FM has entered a new era for the National Capital Region by adopting a Tropical presentation, with reggaetón and bachata beats debuting Thursday as Urban One shifted its Black Gospel “Praise” format to an FM translator and far-suburban Class A FM.