Answer:
A remote isolated region.
Explanation:
In general terms, a 'hearth' is where a phenomenon emerges and develops into something popular. It is the place of origin for things or events that become a sensation or popular in the future.
Among the options given in the question, the least likely place for a "hearth" is an isolated region remotely located. There is no scope of that isolated place to be a source or place of origin for an influential and popular global culture. For a place to be the center of a global phenomenon, it needs to be in a much more populated or even influential place, a bit more habitable than an isolated region.
