Manufacturing Industry Has Long Been Seen as the "Key" to Economic

Manufacturing industry has long been seen as the "key" to economic growth. Its spread from the core to poorer countries since the 1970s has been due to what primarily?

A) import substitution policies
B) shift of labour-intensive production by multinationals to low wage countries
C) government policies to attract foreign investment plus favourable factor conditions for multinationals
D) shifting terms of trade between primary commodities and manufactured goods