In "DAS BOAT", how did the crew raise the submarine from the bottom of the ocean?

A) High Pressure air puched out the water from trimming tanks


B) The engines turned a propeller which pushed the submarine up.


C) The submarine fired a torpedo


D) Grappling gear was used.

In "DAS BOAT", how did the crew raise the submarine from the bottom of the ocean?
Its been a few years since I watched the movie, but it definitely was not C or D. I'm pretty sure it was A.