A. Elements have possibly multiple primary classifications, one secondary classification, and one subclassification.

B. Elements have one primary classification, one secondary classification, and one subclassification.

C. Elements have possibly multiple primary classifications, possible multiple secondary classifications, and possibly multiple subclassifications.

D. Elements have one primary classification, possibly multiple secondary classifications, and possibly multiple subclassifications.

E. Elements have one primary classification, one secondary classification, and possibly multiple subclassifications.