In the van Arkel method, the metal iodides are usually more volatile than the pure metal. Therefore, the metal iodides:
Stay near the top of the reactor
Stay near the bottom of the reactor
Condense and solidify at the bottom of the reactor
Condense and solidify at the top of the reactor
In the van Arkel method, the metal iodides are more volatile than the pure metal, so they condense and solidify at the top of the reactor.
Hence option 4 is correct.