**Core Concept**
DNA fingerprinting is a technique used to identify individuals by analyzing their unique DNA patterns. This technique relies on the presence of specific sequences in the DNA that vary between individuals. The basis of DNA fingerprinting lies in the concept of genetic variation, particularly in the number of repetitions of specific DNA sequences.

**Why the Correct Answer is Right**
Variable Number Tandem Repeats (VNTRs) are short sequences of DNA that are repeated multiple times in a specific order. These repeats are highly variable in their length and are scattered throughout the genome. The uniqueness of an individual's VNTRs makes them an ideal target for DNA fingerprinting. The analysis of VNTRs involves the use of restriction enzymes to cut the DNA at specific recognition sites, followed by gel electrophoresis to separate the fragments based on their size. This technique allows for the identification of individuals based on their unique VNTR patterns.

**Why Each Wrong Option is Incorrect**
**Option A:** Constant Tandem Repeat - This option is incorrect because constant tandem repeats do not vary between individuals, making them unsuitable for DNA fingerprinting.

**Option C:** Non-repeatative sequence - This option is incorrect because non-repeatative sequences do not exhibit the variability required for DNA fingerprinting.

**Option D:** Exon - This option is incorrect because exons are coding regions of genes and do not provide the necessary variability for DNA fingerprinting.

**Clinical Pearl / High-Yield Fact**
DNA fingerprinting is a powerful tool for forensic identification and has been used in numerous high-profile cases. The technique relies on the uniqueness of an individual's VNTRs, which are inherited in a Mendelian fashion.

**✓ Correct Answer: B. Variable Number Tandem Repeats (VNTR)**