Answer:
B) As long as the Fed's announcement is credible, workers and firms will reduce their consumption and investment spending, which will reduce aggregate demand and reduce inflation.
Step-by-step explanation:
If the FED announces that it will increase the federal funds rate, it will increase the interest that banks charge other banks for lending them money in order to comply with the reserve ratio. This increase would make banks hand out less loans and be more careful in order to reduce their need for overnight funds.
If banks reduce their loans, their capacity for creating money will also be reduced, lowering the consumption level and investment spending of both workers (households) and private firms.