AIIMS 2018 Physics Doppler Effect MCQ Question

On the same path, the source and observer are moving such a ways that the distance between these two increases with the time. The speeds of source and observer are same and equal to 10 ms⁻¹ with respect to the ground while no wind is blowing. The apparent frequency received by observer is 1950 Hz, then the original frequency must be (the speed of sound in present medium is 340 m/s)