The word "shackles" in the last sentence of the first paragraph most probably means ______.

A．Trade War between Japan and the US
B．It's time to Remove Japanese Trade Barrier
C．The US Desires to Reduce a Japanese Surplus in Trade
D．Why Japan Won't Submit to US Trade Demands

A．Resistance from a large number of big enterprises against foreign competition.
B．Hindrance of business and government to imported goods that threaten domestic markets.
C．Firm support for import restrictions among Japanese workers, one of the powerful political forces.
D．Historically formed bureaucracy which makes laws and regulations and enforces them.