(d) the speed does not depend on the initial direction.
Explanation:-
When the stone is thrown its total mechanical energy = K.E.+P.E.
= ½mv² + mgh ---------(i)
This energy is conserved and when near the ground its P.E. is also converted to K.E. because of h=0. suppose it hits the ground with speed v', its total energy
= ½mv'² -----(ii)
equating (i) and (ii) we get,
½mv'²=½mv²+mgh v'²=v²+2gh
Clearly v' depends only on the value of v whatever be the initial direction.