JEE Advanced 2017 Physics question

A person measures the depth of a well by measuring the time interval between dropping a stone and receiving the sound of impact with the bottom of the well. The error in his measurement of time is seconds and he measures the depth of the well to be meters. Take the acceleration due to gravity ms and the velocity of sound is 300 ms. Then the fractional error in the measurement, , is closest to

• (A)0.2%
• (B)1%Correct
• (C)3%
• (D)5%