Which of these situations would have been considered blacklisting?

I believe the answer is: A manager refuses to hire a worker who is in favor of unions

blacklisting refers to the actions made by entities to avoid a certain group of people which are in a similar situation.

Union workers are known to cause problems for employers and disrupt the working schedule that is set by managers. So, employers in industries tend compile union workers name into a list and share it with each other so they can prevent them from obtaining jobs.

world bank is the correct answer.

for many centuries there were important factors which the economies of the muslim empires developed increasingly. they applied economic procedures in production, investment, finance, taxation and property. they used to tax certain goods (for example: harvest), they charged interest on money lent, they signed contracts with merchants; they relied on a common currency, and they used checks as well as promissory notes. with the money collected by means of taxation, the government provided the needy with an income. in addition, trading networks covered huge distances, so far regions started to have contact and exchange goods. this trade network covered areas of asia, africa and europe.