Which one of the following options is a pair of equivalent rational number?

A

$$\frac{24}{40}$$ and $$\frac{35}{50}$$

B

$$\frac{-25}{35}$$ and $$\frac{-55}{77}$$

C

$$\frac{-8}{15}$$ and $$\frac{-24}{48}$$

D

$$\frac{9}{72}$$ and $$\frac{-3}{21}$$