There are several information's of immense importance already given in the question.
Velocity of sound = 1560 m/s
Time taken for the echo to reach surface = 1.20 second
We already know
Distance = Velocity * Time
= 1560 * 1.20 meter
= 1872 meter
So the total distance that the sound travels going down and up = 1872 meter
Then
The depth of the bottom = 1872/2 meter
= 936 meter
= 0.92 km
So the correct option is the second option.