The distance travelled by an object in time $$t$$ is given by $$s = 2.5t^2$$. The instantaneous speed of the object at $$t = 5$$ s will be :

A

$$25$$ m s$$^{-1}$$

B

$$5$$ m s$$^{-1}$$

C

$$62.5$$ m s$$^{-1}$$

D

$$12.5$$ m s$$^{-1}$$