Which is the first level of the Orange Book that requires classification labeling of data?

A.
B3

B.
B2

C.
B1

D.
C2

Explanation:
C: These assurance ratings are from the Orange Book. B levels on up require security labels be used, but the question asks which is the first level to require this. B1 comes before B2 and B3, so it is the correct answer.