The length of human DNA is approximately

The length of human DNA is approximately 2.2 meters when considering a single cell. This remarkable length is achieved through the DNA's highly compact structure, allowing it to fit within the microscopic confines of a cell's nucleus. Each human cell contains about 6.4 billion base pairs of DNA, which, if stretched out, would measure around 2.2 meters.

Given that the human body comprises approximately 37.2 trillion cells, the total length of DNA in the entire body would be about 2.0 × 10¹³ meters, which is nearly 70 times the distance from the Earth to the Sun and back.

Therefore, the correct answer is:

c) 2.2 meters considering only one cell of human body.