A

Test question analysis: A. The sum of the relative atomic masses of the carbon atoms in tannin is 12×72=864, and the relative atomic mass of the hydrogen atoms The sum of the masses is 1×52=52, the sum of the relative atomic masses of the oxygen atoms is 16×46=736, and the sum of the relative atomic masses of the carbon element is the largest, then the mass fraction of the carbon element is the highest, so the option statement is wrong.

B. Tannin is composed of three elements: carbon, hydrogen and oxygen, so the option statement is correct.

C. A tannin molecule is composed of 76 carbon atoms, 52 hydrogen atoms and 46 oxygen atoms. Each tannin molecule contains 76+52+46=174 atoms. Therefore, the option statement is correct.

D. From the chemical formula of tannin, it can be seen that tannin is a compound containing carbon elements and is an organic matter, so the option statement is correct.

So choose A.

Comments: This question is not very difficult. It tests students’ ability to combine new information and flexibly use the meaning of chemical formulas and related calculations to analyze and solve problems.