One Lesson Policymakers Have Learned, and Which Was Evident from Japan's

One lesson policymakers have learned, and which was evident from Japan's experience in 2002, is:

A) An intervention in the foreign exchange market will not work unless accompanied by a change in the interest rate
B) An intervention in the foreign exchange market is almost always effective if done on a regular basis
C) In order for foreign exchange interventions to work, they must be frequent and expected
D) For an intervention in the foreign exchange market to work, the interest rate must be held constant by the central bank