Final answer:
Option (B), The term used to describe the wide, rolling, grassy plains through which nomadic herds were followed is 'steppes', particularly referring to the Eurasian Steppe.
Step-by-step explanation:
They followed their herds through the wide, rolling, grassy plains called steppes. The Eurasian Steppe is a vast stretch of grassland running from Eastern Europe over to central Asia and China into Mongolia. This area historically has been home to nomadic pastoralists who grazed herds and has distinct cultural significance due to the people that migrated and lived there.
Steppes in particular are characterized by their similar climate and vegetation which are well-suited to pasturing livestock but less welcoming to settled agriculture compared to savannas in Africa or prairies in North America.