Which of These Messages Would Probably Be Most Persuasive

Which of these messages would probably be most persuasive?

A) We can save animal species from extinction, but only if we get big contributions now.
B) We are counting on you personally to contribute enough to save some animal species.
C) Even a modest contribution can help save many endangered species.
D) Many animal species are already extinct or almost extinct, and the need is almost hopeless.