please help i am stuck on this question

Answer:
[tex]C.\ \frac{10}{15} \times\frac{5}{4}[/tex]
Step-by-step explanation:
Therefore,
dark shaded's length = [tex]\frac{10}{15}[/tex] of the light shaded's length
[tex]=\frac{10}{15} \times\frac{5}{4}[/tex]