Research on Managed Exchange Rates by Economists Bordo and Schwartz

Research on managed exchange rates by economists Bordo and Schwartz shows that dirty floats

A) have very large and significant effects on the values of world currency.
B) are trivial in size relative to total currency trading and have little if any effect.
C) are having an increasingly more powerful role in the world money markets.
D) are more successful when used by G-8 countries.