Ablue whale makes a call underwater at the same time as an elephant calls on land. how long will it take each of these sounds to travel 3 km

 sound in water=4.3 speed of sound in air ( = 343.2 m/s) at 20 deg.C

Of we take sound V as 343m/s the elephant will take 8.75sec.
and in the water the sound V is 1493m/s the whale will take 2.01sec.

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The correct answer is b