Let’s go by elimination of the choices.
If Y is a solid at 20o C, it’s freezing point cannot be less than 200 C because freezing point is equal to melting point. So (3) with 120 C is out.
If X is a liquid at 250 C, it’s freezing point cannot be higher than 250 C because freezing point is also melting point so a lower temperature must have turned X into a liquid. So (2) with 400 C is out.
The 2 substances are in the same state at 870 C, so we may think either both are liquids or both are gases. Option (1) X’s boiling point is 800 C, below 870 C and Y is 1200 C above 870 C so they cannot be in the same state as X is a gas and Y is still not yet.
That leaves option (4) as the answer, and if you check the temperatures, most likely X and Y are both in liquid state at 870 C.