The correct answer is "D)". When Willie deposits those $ 250 in his savings account and the other $ 100 in his checkings account he is, effectively, allocating that money as a "store of value". In other words, an asset that maintains its value without depreciating.
Regarding option "A", one does not have the information about Willies marital status. Therefore one cannot infer that his household income is $55000 because we donĀ“t know if there are other people living with him that have income.
Regarding option "B", Willies income is not only used as a medium of exchange for goods but also as an asset when he puts it onto his accounts.
Regarding option "C", operating on a "cash only" basis is an option. However, one could exercise other financing methods that also be considered smart. It depends on the financial status of a person.