That is why I am leaning to Option #3, if you are in the City you state you are in the City. If you are outside the City of Pittsburgh you almost always know which rivers you are between so you can state between which rivers you are.
For Example most of the City of Pittsburgh is between the Allegheny and Monongahela Rivers (For Example Downtown, Oakland, East Liberty, The Hill District etc). Some People live South of the Monongahela (South Side, Mt Washington, Beechview, Banksville, Brookline, West End etc). Other live North of the Allegheny (North Side, Manchester, etc). If you live in ANY neighborhood of the City of Pittsburgh I would have you list yourself as in the City of Pittsburgh.
The other three divisions are for the Suburbs (Or for those City Residents who prefer to be listed between the Rivers).
Between the Monongahela and Allegheny Rivers:
Borough of Braddock
Borough of Braddock Hills
Borough of Churchill
Borough of East McKeesport
Borough of East Pittsburgh
Borough of Edgewood
City of McKeesport
Municipality of Monroeville
North Braddock Borough
Municipality of Penn Hills
Borough of Pitcairn
Borough of Plum
South Versailles Township
Borough of Trafford
Borough of Turtle Creek
Borough of Versailles
Borough of Wall
Borough of White Oak
Wilkins Township
Borough of Wilkinsburg
Borough of Wilmerding
South of the Ohio and Monongahela Rivers:
Borough of Baldwin
Baldwin Township
Bethel Park
Borough of Brentwood
Borough of Bridgeville
Borough of Carnegie
Borough of Castle Shannon
City of Clairton
Collier Township
Borough of Coraopolis
Borough of Crafton
Crescent Township
Borough of Dormont
City of Duquesne
Findlay Township
Borough of Green Tree
Borough of Heidelberg
Borough of Homestead
Borough of Ingram
Borough of Jefferson Hills
Kennedy Township
Borough of McDonald
Borough of McKees Rock
Moon Township
Municipality of Mt. Lebanon
Borough of Mt. Oliver
Borough of Munhal
North Fayette Township
North Versailles Township
Borough of Oakdale
Pennsbury Village
Borough of Pleasant Hills
Robinson Township
Borough of Rosslyn Farms
Scott Township
South Fayette Township
South Park Township
Stowe Township
Borough of Thornburg
Upper St. Clair Township
Borough of West Elizabeth
Borough of West Homestead
Borough of West Mifflin
Borough of Whitaker
Borough of Whitehall
North of the Ohio and Allegheny Rivers (Excluding the Ohio Valley):
Borough of Aspinwall
Borough of Blawnox
Borough of Brackenridge
Borough of Bradford Woods
Borough of Chalfant
Borough of Cheswick
Borough of Dravosburg
East Deer Township
Borough of Etna
Fawn Township
Borough of Forest Hills
Borough of Fox Chapel
Borough of Franklin Park
Frazer Township
Borough of Glassport
Hampton Township
Harmar Township
Harrison Township
Indiana Township
Marshall Township
Town of McCandless
Borough of Millvale
Borough of Oakmont
O'Hara Township
Pine Township
Borough of Rankin
Reserve Township
Richland Township
Ross Township
Shaler Township
Borough of Sharpsburg
Borough of Springdale
Springdale Township
Borough of Swissvale
Borough of Tarentum
Borough of Verona
West Deer Township
Borough of West View
Ohio Valley:
Aleppo Township
Borough of Avalon
Borough of Bell Acres
Borough of Bellevue
Borough of Ben Avon
Borough of Ben Avon Hts.
Borough of Edgeworth
Borough of Emsworth
Borough of Glenfield
Borough of Haysville
Kilbuck Township
Leet Township
Borough of Leetsdale
Borough of Sewickley
Borough of Sewickley Hts.
Borough of Sewickley Hills
Ohio Township
Borough of Osborne
Between the Mongahelia and Youghiogheny Rivers:
Borough of Elizabeth
Elizabeth Township
Forward Township
Borough of Glassport
Borough of Liberty
Borough of Lincoln
Borough of Port Vue
Exception:
City of Pittsburgh (North, South and between all three Rivers)
Neville Township (On Neville Island IN the Ohio River)
http://www.county.allegheny.pa.us/economic/munis/index.asp