Thanks Anne. Since that post, I've learned that ST uses all 4 of the major carriers, depending on the phone in question. So if one prefers one carrier over another, it will pay to do some research to discover what phones are covered by each carrier.
I wish ST made that information readily available so that the phone choice process would operate much smoother. Is there a reason one has to dig to discover the carrier for each phone?
The link that Jennifer posted above does contain many phones with -c and -g designators, but none of the Android phones have that information. I thought that phones with a T designator are TMobile network phones.
And the Android phones appear to be:
ZTE Merit - AT&T
Galaxy Proclaim - VZW
Optimus Q, Optimus Black, and Galaxy Precedent - Sprint