**Core Concept**
Fredrich's ataxia is a rare genetic disorder characterized by progressive damage to the nervous system. The underlying cause of this condition is a mutation in the FXN gene, which codes for the protein frataxin. This mutation affects the mitochondrial function, leading to impaired energy production in neurons.

**Why the Correct Answer is Right**
The correct answer is related to the type of mutation that affects the FXN gene. Fredrich's ataxia is caused by an **expansion of a GAA trinucleotide repeat** in the first intron of the FXN gene. This expansion leads to reduced expression of the frataxin protein, which is essential for maintaining the integrity of mitochondria. The loss of frataxin function disrupts mitochondrial energy metabolism, resulting in the characteristic symptoms of Fredrich's ataxia.

**Why Each Wrong Option is Incorrect**
**Option A:** point mutation - A point mutation is a single nucleotide change in the DNA sequence, which is not the primary cause of Fredrich's ataxia.
**Option B:** deletion mutation - While deletions can cause genetic disorders, the primary mutation in Fredrich's ataxia is an expansion of a trinucleotide repeat, not a deletion.
**Option C:** frameshift mutation - Frameshift mutations are caused by insertions or deletions of nucleotides that alter the reading frame of the genetic code, which is not the primary mechanism of Fredrich's ataxia.

**Clinical Pearl / High-Yield Fact**
Remember that Fredrich's ataxia is an autosomal recessive disorder, meaning that a person must inherit two copies of the mutated gene (one from each parent) to develop the condition.

**Correct Answer: C. Frameshift mutation**