Assume the correct answer is 25%. Then A and D are correct, so your chance of randomly guessing the right answer is 50%, which contradicts our initial assumption. That assumption leads to a contradiction.
Assume the correct answer is 50%. Then B is correct, so your chance of randomly guessing the right answer is 25%, which also contradicts our initial assumption. That assumption also leads to a contradiction.
(By the same reasoning 0% is also not the correct answer).
Hence none of the available answers are correct.
A simpler version of the same paradox:
Will you answer to this question be "No"? A. Yes. B. No.
Assume the correct answer is 25%. Then A and D are correct, so your chance of randomly guessing the right answer is 50%, which contradicts our initial assumption. That assumption leads to a contradiction.
Assume the correct answer is 50%. Then B is correct, so your chance of randomly guessing the right answer is 25%, which also contradicts our initial assumption. That assumption also leads to a contradiction.
(By the same reasoning 0% is also not the correct answer).
Hence none of the available answers are correct.
A simpler version of the same paradox:
Will you answer to this question be "No"?
A. Yes.
B. No.