The answer is A) accumulation zone
Answer:

Explanation:
As we know that moment of force is given as

now we have


now from above formula we have

here we know that

so we have


What you need to know is that the force is
F=ma
The force is the product of mass and acceleration
this means that the acceleration is
a=F/m
a) The force is halved?
this means that f will be

now:
a=

So the accelaration will also he halved (it's the original acceleratation divided by 2)
b) The object's mass is halved?
a=

=a=

which is the original acceleration times two!! so it will double
c) The force and the object's mass are both halved?
now we have
a=

=a=

=a=

so they will cancel each other out and the acceleration will stay the same!