Correct answer: D). Duplication
It is a disease that is caused by the repetition of codon for many times, which will lead to inactivation of gene that is required for the proper function of brain and other body functions. It is a sex linked genetic disorder, which is caused to to lengthening or expansion of genes.
In these disease the codon triplet CGG is repeated several times, which causes mutation in the gene CFR1. The main symptoms of this disease is mental impairment and heart problem etc.