Approximately 200 of the 300 Native Species of Fish in Lake

Multiple Choice

Approximately 200 of the 300 native species of fish in Lake Victoria haven't been observed since the 1960s and are therefore probably extinct. Using the estimate of the background extinction rate, how many species of Lake Victoria fish would one expect to have naturally become extinct during the last 50 years?

A) less than 1
B) 1-10
C) 11-50
D) more than 50