The correct answer is B
Let assume f(n) = n ^ 4
g(n) = n ^ 2
f(n) = n ^ 2
after putting these values, you will get the answer.
Someone can say that it will fail for f(n) = n^5. But see the interesting answer it will work for f(n) = n ^ 3 and f(n) = n ^ 4 But if you see the other option they will fail more easily like option A for f(n) = n ^ 3 , g(n) = n , h(n) = n ^ 2. similarly you can find for the others. So I think the correct answer is B.