What Is the Difference Between Background Extinction and Mass Extinction

Multiple Choice

What is the difference between background extinction and mass extinction?

A) background extinction is continuous and low-level; mass extinction occurs during a relatively short period of time and involves large numbers of species
B) background extinction is indiscriminate; mass extinction targets particular species
C) background extinction may be due to a human induced catastrophic event; mass extinction is a natural biological process
D) background extinction has occurred 5-6 times throughout Earth's history; mass extinctions have occurred hundreds of times
E) background extinction is a synonym for mass extinction