Answer:(a)does not change
Step-by-step explanation:
Given
Submarine is 50 m below the surface
Now submarine descends to 100 m and stops
As we know that pressure difference at a depth of h is given by
![P=\rho gh](https://img.qammunity.org/2020/formulas/physics/college/u9ss5r5f8apaqu2xrkhxj3knn5ymivzgn5.png)
where
=Density of fluid
g=acceleration due to gravity
h=height below free surface of liquid
buoyant force is equal to volume displaced by object
as the submarine is already in water therefore buoyant force will remain same.