A Pregnancy Questionnaire Inquired as to the Educational Level of Expectant

Multiple Choice

A pregnancy questionnaire inquired as to the educational level of expectant mothers. The fields used a set of options such as SHS (some high school) , HSD (high school diploma) , SC (some college) , BD (bachelor's degree) , MD (master's degree) , and DD (doctoral degree) . This is an example of what type of data constraint?

A) Range
B) Unique
C) Foreign-key
D) Set-membership