Explain please

Question 7 1 pts Which of these risks will a diversified investor likely need to worry about? a. A computer hack erases all electronic financial records of everyone in the country. b. A firm's key advertising executives quit to start their own company c. A highly contagious virus emerges that turns humans into zombies. O a only O bonly O conly O a and b O a and c O b and c O all of them