Compressional wave impulses are sent to the bottom of the sea from a ship, and the echo is heard after 2 s. If the bulk modulus of water is 2×10^9 N/m² and the mean temperature is 4°C, then the depth of the sea is:
(A) 2000×10^3 m
(B) 2828 m
(C) 1414 m
(D) 707 m