One Person Has a Very Messy Apartment While Another Person

Multiple Choice

One person has a very messy apartment while another person has a very neat apartment. What procedure(s) is (are) necessary to use a need for order to explain the difference in the messiness of their apartments? The procedure involves

A) showing the location of the need for order on Maslow's hierarchy of needs.
B) devising a rating scale for measuring the need for order.
C) showing that scores from a need-for-order scale correlate with messiness/neatness of an apartment.
D) answers b and c are both necessary