This kingdom was called the "hermit kingdom" because of its lack of contact with outside influences.
japan
china
korea
taiwan

It was "Korea" that was called the "Hermit Kingdom" because of its lack of contact with outside influences, (specifically North Korea in later years), since it was very isolated politically and economically. 

Its is d. because i did it

1. 5-8 weeks 2. better care of captured africans