Answer:
B. a well respected chairman of the Federal Reserve suddenly resigns
Step-by-step explanation:
A non diversificable risk is a risk that cannot be eliminated by diversifying a portfolio. It is dependent on the market conditions. E.g. recession, war.
A diversificable risk is a risk that can be eliminated by diversifying a portfolio. Examples include: a key employee suddenly resigns and accepts employment with a key competitor, a well managed firm reduces its work force and automates several jobs.
I hope my answer helps you.