Answer:
D. All of these choices are correct.
Explanation:
A SNP (Single Nucleotide Polymorphism) is a variation, in the sequence of the DNA between different individuals, of a single nucleotide (A, T, G or C) in a particular position of the genome.
The variants of the DNA sequences are called alleles.
The variation must be present in at least 1% of the general population to be considered a polymorphism instead of just a point mutation.