Why is the gold silla crown evidence of trade relations between early korea and other parts of asia?

The connection between Korea and other Asian parts can easily be seen in the Silla crown. The outer parts of the crowns show clear evidence of influence from the Scytho-Iranians from Central Asia, as well as the tree motif of the crown which is connected with both Iranian and Siberian shamanism of the symbolic of the tree. Also, some of the material from which the crowns have been made originates as far as the Mediterranean region, and while some have speculated that maybe there's a Greek or Etruscan influence, it is most commonly seen as a Persian influence.

the correct answer is b, "fertility rates are increasing, so populations will grow more quickly in the future."