Which thematic progression pattern has been used in this paragraph？ Hemp？s environmental credentials are indisputable. It grows better in organic systems than in conventional ones. It smothers weeds and controls pests, clearing the land for other crops. It improves the structure of the soil, with strong roots to prevent erosion. If processed in the field, it returns nutrients to the land and purports to ,clean up？ soil contaminated with heavy metals. It is one of a minority of textile-fibre crops that can be grown in temperate climates. So why, given its potential, is so little hemp used today？ (New Internationalist, June 1998, p. 14)

A. simple linear progression
B. split progression
C. constant progression
D. derived hyperthematic progression