$IUCN$ Red List $(2004)$ documents the extinction of $\underline{A}$ species in the last $\underline{B}$ years.

• A
  $A - 500, B - 300$
• B
  $A - 784, B - 500$
• C
  $A - 654, B - 500$
• D
  $A - 984, B - 300$