Where should the hyphen be placed?
An ex high school standout, he enjoyed a stellar college career at the University of Kansas.
An ex-high school standout, he enjoyed a stellar college career at the University of Kansas.
An ex high school standout, he enjoyed a stellar college-career at the University of Kansas.
An ex high school standout, he enjoyed a-stellar college career at the University of Kansas.
An ex high-school standout, he enjoyed a stellar college career at the University of Kansas.
An ex-high school standout, he enjoyed a stellar college career at the University of Kansas.
The correct placement of the hyphen in the given sentence is:
An ex-high school standout, he enjoyed a stellar college career at the University of Kansas.