Which of the following mutations would be least likely to have any discernible phenotype on the individual?

A. Translocation of the last 1,000 base pairs of chromsome 1 onto chromosome 2.
B. Nondisjunction of chromosome 7 to produce trisomy-7 (*2n+1)
C. Nondisjunction of chromosome 8 to produce monosomy-8 (*2n-1)
D. Deletion of 400 base pairs, resulting in the loss of an enhancer.