Step 1: Understand centre of mass.
The centre of mass is the point where the entire mass of a system can be considered to be concentrated for motion analysis.
Step 2: Dependence on mass distribution.
The position of centre of mass depends on how mass is distributed in the system. Different distributions give different positions.
Step 3: Analyze option (A).
In translatory motion, the centre of mass moves along with the body, so it does not remain fixed. Hence incorrect.
Step 4: Analyze option (B).
The position changes with coordinate system representation but physical location remains independent. Hence incorrect.
Step 5: Analyze option (C).
Shape and size influence how mass is distributed, so this statement is incorrect.
Step 6: Analyze option (D).
This is correct because centre of mass is determined by mass distribution.
Step 7: Final conclusion.
\[
\boxed{\text{Depends on the distribution of its mass}}
\]