Given in the question, blue eyes is recessive trait and brown eyes is the dominant trait
For blue eyes, the genotypes are bb (as the trait is recessive)
For brown eyes, the trait would be BB or Bb
BB is the homozygous dominant and Bb is the heterozygous trait where B is dominant over b
In the question itself, it is shown B= brown eyes and b= blue eyes
When the allele is represented with a capital letter it is dominant and when it is represented with small letter, then it is recessive.
There are two cases possible
1.
[tex]\begin{bmatrix}{\placeholder{⬚}} & {B} & {b} \\ {b} & {Bb} & {bb} \\ {b} & {Bb} & {bb}\end{bmatrix}[/tex]Here the Bb are brown and bb are blue, also the ratio of Bb and bb is 1:1, the parental genotypes would be Bb and bb resulting in babies with brown and blue eyes
2. In second case
[tex]\begin{bmatrix}{\placeholder{⬚}} & {B} & {B} \\ {b} & {Bb} & {Bb} \\ {b} & {Bb} & {Bb}\end{bmatrix}[/tex]Here the genotypes of the progenies will have brown eyes only.
The first case would justify the condition.