In which situation does the law of conservation of momentum apply? 1.) in the absence of greatest velocity 2.) in the presence of least velocity 3.) in the absence of outside forces 4.) in the presence of outside forces

As per Newton's II law we know that

rate of change in momentum is Net outside force on the object

now here we will have if net outside force will be zero

then we can say

so from above equation we can say

and hence we have

so the correct answer will be

3.) in the absence of outside forces