If we use $\leq$ to denote asymptotically less than or equal to, we can write
$f(n) = O(g(n))$ and $h(n) = O(g(n))$ as $f \leq g$ and $h \leq g.$
Now, the given choices can be written as
A. $f \leq h.$ Possible
B. $g \leq f.$ Possible when $f = g.$
C. $h \geq g.$ Possible when $h = g.$
So, none of the given options are necessarily FALSE.
Correct Option: D