Classify three of the following events as mostly systematic or mostly unsystematic. Explain if the distinction clear in every case and why?

a. Short-term interest rates increase unexpectedly.

b. The interest rate a company pays on its short-term debt borrowing is increased by its bank.

c. Oil prices unexpectedly decline.

d. An oil tanker ruptures, creating a large oil spill.

e. A manufacturer loses a multimillion-dollar product liability suit.

f. A Supreme Court decision substantially broadens producer liability for injuries suffered by product users.