Kim asked whether this was from a city bike:
http://ebay.com/
To which Ado pointed out: Judging by the distance between chainring and crank arm (14mm) I'd say this is for a bike with a chain guard, so probably for a city bike.
Just as important are the fact that the the chainring is suaged and non-replaceable and has only 40 teeth. It cannot be anything beyond a city bike.
Steven Maasland
Moorestown, NJ