Answer:
Heterozygous genotype would be Ff
Explanation:
In a heterozygous genotype, one allele is taken from one set of allele pair and another allele is taken from all together a different allele pair in a way that the two alleles in it are distinguish.
For this case, the two alleles are black fur (F) and brown fur (f)
Black fur (F) is dominant to brown fur (f)
Homozygous genotype would be FF and ff
Heterozygous genotype would be Ff