Why is this dietary supplement best characterized as a mixture instead of a pure substance? A. The percent daily value is less than 100 percent
B. Calcium citrate is composed of nonmetallic elements
C. A tablet contains different chemical compounds
D. Calcium citrate contains more than one element.

C. A tablet contains different chemical compounds

Explanation:

The dietary supplement in this question depicts a kind of matter. Matter, in chemistry, can either be a pure substance or a mixture. Unlike elements and compounds (pure substances) which cannot be separated by physical means, mixtures can be separated using physical method.

A mixture is a combination of different substances with varying physical properties, which serves as basis of their physical separation. According to the image in the question, the Calcium citrate dietary supplement contains different chemical compounds like polyethylene glycol, sodium, methyl cellulose, magnesium silicate etc.

These chemical compounds retain their individual properties and can be separated easily via physical techniques, hence, the dietary supplement is a MIXTURE.