an intervening opportunity is an example of a
a.
push factor
b.
pull factor
c.
low standard of living
d.
destination for periodic migration

B.  pull factor

Explanation:

A pull factor is a factor that is associated with some sort of opportunity or any significant chance to change and is chartered the economic perspective such as a job or the development of a good standard of living. The pull factor here can be seen in items of the good housing and the availability of the these factors which make the place of destination seem more suitable and rewarding.

Exposed great deposits of coal and iron ore