there are 5 white blocks and 4 gray blocks.
so the ratio of the gray square to white square is,
[tex]\frac{\text{gray}}{\text{white}}=\frac{4}{5}[/tex]
multiply numerator and denominator by 5.
[tex]\frac{\text{gray}}{\text{white}}=\frac{4}{5}\times\frac{5}{5}=\frac{20}{25}[/tex]
so the answer is option D
