In the horse, the $(A)$ locus controls the distribution of pigment in the coat. There are $4$ different alleles at the $(A)$ locus. The $(A^{+})$allele causes the bay phenotype. $(A)$ causes a bay phenotype but with a dark mane and tail. The $(a^t)$ allele produces a seal brown phenotype and the $($a$)$ allele produces a black horse. The order of dominance at this locus is $A^{+}>A>a^t>$ a$.$ Using the allele frequencies of the above alleles shown below, at what frequency in this population would you expect a seal brown horse to be produced?

$A^{+}=0\mathrm{.}4,A=0\mathrm{.}2,a^t=0\mathrm{.}1,a=0\mathrm{.}3$

$0\mathrm{.}02$

$0\mathrm{.}06$

$0\mathrm{.}075$

$0\mathrm{.}01$

$0\mathrm{.}1$

$0\mathrm{.}07$