How is the preferred level status set for suppliers?

How is the preferred level status set for suppliers?
A . List from 1 (Lowest Preference) to 3 (Highest Preference)
B. List from 3 (Lowest Preference) to 1 (Highest Preference)
C. List from 5 (Lowest Preference) to 1 (Highest Preference)
D. List from 1 (Lowest Preference) to 5 (Highest Preference)

Answer: D