Answer:a. He may need to rethink and evaluate his decision first considering things like his home will be vulnerable to severe brunt of storm caused by waves .
Secondly these islands tend to be vulnerable to severe rate of erosion and deposition of sand.
In order to deal with these issues and trying to mend them or resolve them or making them less intensive it will cost him a lot and will be a hustling process.
It will be highly reasonable to first think about this carefully, evaluate all the consequences and see if the disadvantages outweigh advantages which may be the sign to deeply consider his decision to buy this house.