During the 1960s, many Keynesian economists felt that by studying the Phillips curve

A) policy makers could fine-tune the economy by selecting policies that would produce the exact mix of unemployment and inflation that suited current government objectives.
B) policy makers could eliminate even frictional unemployment in the economy.
C) the President and Congress did not need to attempt to balance the budget.
D) policy makers could dispense with the Federal Reserve's open-market operations.

A