Black fur (B) is given dominant, and white (b) is therefore recessive.
If there is at least one white fur among the offsprings, both black fur parents must be heterozygous, or Bb.
The possible genotypes of the offsprings are therefore those shown in a Punnett square, as follows
B b
B BB Bb
b Bb bb
Or, the possible genotypes are {BB, Bb and bb} [ no distinction between Bb and bB]