Albinism is a recessive disorder in which the skin and hair fail to produce pigment. The following question(s) ask you to evaluate the pedigree chart shown here in which "N" is the allele for normal pigmentation and "n" is the allele for albinism. The shaded circles for Deirdre and Shannon represent the only individuals expressing the disorder. According to the pedigree above, who is a not a carrier of albino?
A. Aaron
B. Bill
C. Brandon
D. All of the above are carriers of albino

D. All of the above are carriers of albino

Explanation:

Now according to pedigree:

1st generation both male and female are carriers of albino and in result of that Dierdre is disordered (nn) and when Dierdre (nn) is married to person who is carrier (Nn) because their daughter Shannon is also disordered (nn). It means one allele from mother (nn) and one allele from father (Nn) comes and affect the Shannon (nn).

As mother Dierdre is effective having both nn alleles so everytime she share n allele to her offsprings.

So, according to explanation above Aaron, Bill and Brandon all are carriers of albino.

that is wrong, its not thymus.