Correct option is C. $$20\ g$$
Suppose $$'m'$$ gram of water evaporates then, heat required
$$\triangle Q_{req} = mL_{v}$$
Mass that converts into ice $$= (150 - m)$$
So, heat released in this process
$$\triangle Q_{rel} = (150 - m) L_{f}$$
Now,
$$\triangle Q_{rel} = \triangle Q_{req}$$
$$(150 - m)L_{f} = mL_{V}$$
$$m(L_{f} + L_{v}) = 150 L_{f}$$
$$m = \dfrac {150L_{f}}{L_{f} + L_{v}}$$
$$m = 20\ g$$.