None of them is correct.
Explanation:
1) why can't be 25% : If the answer is 25%, then as we know two out of four answer choices is '25%', the answer has to be 50%.
This is a contradiction, so the answer cannot be 25%.
2) why can't be 50% : If the answer is 50% then because answer:"50%" is 1 out of 4 answer choices, the answer must be 25%. This is also a contradiction. So the answer cannot be 50%.
3) why can't be 60% : same logic
