[单选题]
You drop a stone into a deep well and hear the splash 2.b:sk8-;oz16uyyqx4 j vf- gn,yft9g w5 s later. How deep ipa jt+t )l5mg-s the well? ()p+l-m5attjg Ignore air resistance, and assume the velocity of sound is 340 m/s.)
A. $25 \; m$
B. $27 \; m$
C. $29 \; m$
D. $31 \; m$
