Data on extinction rates pre and postmass extinction rates suggest that the extinction rate remains ...

Data on extinction rates pre and postmass extinction rates suggest that the extinction rate remains elevated for some time after the mass extinction event. Which of the following are plausible explanations for this ob-servation?
 
  a. The negative effects of the original cause for the mass extinction persist after the original event.
  b. Although not completely extinct, many surviving species are confined to small geographic ranges that make them vulnerable to local extinction events.
  c. High mortality led to the loss of genetic diversity in survivors.
  d. Adaptive radiations after mass extinctions produce new predators and competitors that led to the extinction of mass extinction survivors.
  e. All of the above.