YET ANOTHER CHALLENGE

Congratulations to Cadet Jorge Esquivel, who correctly answered that "C" is correct.  Do you know why?

Here's the latest challenge.  This one is pure logic.  Which of the following is correct?

a.  One of these statements is false.

b.  Two of these statements are false.

c.  Three of these statements are false.

d.  Four of these statements are false.

Which is it, a, b, c, or d?  This challenge will expire at 0730, Wednesday, 20 March.  Good luck.