The correct answer is option 'A': 3164.7 million nucleotides.

Explanation:
The human genome is the complete set of genetic information in humans. It is encoded in the DNA molecules present in the nucleus of every cell. The DNA molecule is composed of a long sequence of nucleotides, which are the building blocks of DNA.

To determine the number of nucleotides in the human genome, we need to consider the size of the DNA molecule and the number of base pairs it contains. The human genome is a diploid genome, meaning that each cell contains two copies of each chromosome. In humans, there are 23 pairs of chromosomes, for a total of 46 chromosomes.

The size of the human genome is typically measured in base pairs (bp) or nucleotides (nt). A base pair consists of two nucleotides that are complementary to each other: adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G).

The estimated size of the human genome is approximately 3.2 billion base pairs. This estimation includes both the coding regions (exons) and the non-coding regions (introns) of the DNA.

To convert the number of base pairs to nucleotides, we need to multiply the number of base pairs by 2, as each base pair consists of two nucleotides. Therefore, the number of nucleotides in the human genome is approximately 6.4 billion.

However, it is important to note that the estimated size of the human genome can vary slightly between individuals. Genetic variations, such as single nucleotide polymorphisms (SNPs), can lead to differences in the number of base pairs between individuals. Therefore, the exact number of nucleotides in the human genome may vary slightly, but the estimated size is around 6.4 billion nucleotides.

In summary, the correct answer is option 'A': 3164.7 million nucleotides, which is equivalent to approximately 6.4 billion nucleotides.