A heat engine operates between a cold reservoir at temperature $\;T_{2}=600 K\;$ & a hot reservoir at temperature $\;T_{1}\;.$ It takes 1000 J of energy from hot reservoir & gives 200 J . What can be the minimum temperature of the hot reservoir

Question

$(a)\;3000\;K\qquad(b)\;1500\;K\qquad(c)\;900\;K\qquad(d)\;1200\;K$