Which one of the following cases is an example of a non-diversifiable risk?

a)	A key technician of a medical corporation suddenly resigns and serves as a manager in a key competitor.
b)	A reputable CEO of a company listed on the New York Stock Exchange suddenly resigns.
c)	Malfunction was found on another Tesla car.
d)	Bank of Canada just announced it will raise the interest rate by 0.25%.
e)	A well-established energy company suddenly announces it will be bankrupted.