From the 118 known elements, 25 elements are believed to be essential to human biology.
Out of 25 elements , 6 elements namely – carbon, oxygen, hydrogen, nitrogen, calcium and phosphorus , they make up about 99% of the human body. Some other elements like - potassium, sulfur, sodium, chlorine, and magnesium, they are also found in the human biology.
Because they don't have a or any cells and have no DNA
D is the answer to this question.