Answer:
llbb
Step-by-step explanation:
The genotype of the black, short-haired otter could be determined by testing-crossing with a brown, long-haired otter whose genotype would be llbb.
Analysis of the resulting zygote from the cross would give an indication of the genotype of the otter - whether it has two dominant alleles each for the black, short-hair traits or heterozygous.
If the otter has two dominant alleles for the two traits, all the resulting zygote from the test-cross would have black, short-hair, but if it is heterozygous, a mixed phenotype set of zygote would be obtained.