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 `eltaT=0.01` seconds and he measures the depth of the well to be `L=20` meters. Take the acceleration due to gravity `g=10 ms^(-2)` and the velocity of sound is `300 ms^(-1).` Then the fractional error in the measurement, `deltaL//L,`is closest to