A vessel employs ultrasound to determine the depth of the sea. The elapsed time between sending a pulse of ultrasound and receiving its echo is $0.52\text{ s}$. The speed of ultrasound in sea water is $1500\text{ m s}^{-1}$. Determine the depth of the sea.
- A$390\text{ m}$
- B$780\text{ m}$
- C$1600\text{ m}$
- D$5800\text{ m}$