Answer:
Half show the wild-type phenotype and half show the mutant phenotype.
Explanation:
The dominant mutation means that the mutation can express itself even in the heterozygous condition as well. The cross between homozygous unaffected wild type (aa) is crossed with the heterozygous (Aa) is as follows;
Parents aa × Aa
progeny: Aa, Aa ( affected ) and aa, aa (unaffected).
Thus, 505 individual are unaffected and 50% individual are affected.
Hence, the correct answer is option (B).