The ratio of speed of the dog to that of the hare is the ratio of distances covered by them in the same amount of time.

Let us assume that speed of the Hare is x units/sec

Then speed of the Dog = (3/5)x units/sec

Now, let us assume that the Hare takes n leaps in t seconds

Then, the Dog takes (3/5)n leaps in t seconds

Therefore, the ratio of the distance covered by the Hare to that of the Dog is

Distance covered by the Hare : Distance covered by the Dog

= (n * x * t) : ( (3/5) * n * (3/5)x *t )

= (n * x * t) : ( (9/25) * n * x *t )

= (25/9) : 1

Therefore, the ratio of the speed of the Hare to that of the Dog is

Speed of the Hare : Speed of the Dog

= (25/9) : 1

= 9 : 5

Therefore, the correct answer is Option D: 9:5

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