95.10 - 2011 has been repealed
The others talk only about built up areas.
CTA/CTR isn't about built up areas, but they may co-exist.
For CTA/CTR (in general) you need an RPC to pilot the plane and you need at least an RPL, or higher, with CTA/CTR endos and a current CASA medical to be in class A, B, C or D airspace. You don't need an Xsponder for Class D but you will for Class E. For built up areas in a Rotax you could talk to Bert Flood, the importer, about which Rotax engine is allowed over built-up areas.