"Scott Migaldi" wrote in message
...

Plain language: Because they do not have the trafic load required to be
Class C but much more traffic than what is being loaded into the class D
airports.

Has nothing to do with traffic levels. We were a TRSA here at BIL and
went right into class C when that all happened across the country. A
very few just stayed TRSA's. Class D is never an option for a facility
with a radar approach control.