Identify a military plane from a lame description

Factual Questions
21

Maybe an Embraer 145?

22

BAe 125, maybe? Might be too small.
http://www.raf.mod.uk/equipment/bae125.cfm

Or a US C-20, but again, bit small:
http://usmilitary.about.com/gi/dynamic/offsite.htm?zi=1/XJ/Ya&sdn=usmilitary&cdn=careers&tm=36&gps=32_1272_1020_611&f=20&tt=14&bt=1&bts=1&zu=http%3A//www.fas.org/man/dod-101/sys/ac/c-20.htm

C-22B (militarized 727)
http://usmilitary.about.com/gi/dynamic/offsite.htm?zi=1/XJ/Ya&sdn=usmilitary&cdn=careers&tm=91&gps=34_1587_1020_611&f=20&tt=14&bt=1&bts=1&zu=http%3A//www.fas.org/man/dod-101/sys/ac/c-22.htm

23

It had a rounded nose, so I’m still going with the C-9. Probably a charter, which explains the lack of distinguishable markings. A hell of a roar of the thing, too.