As we know from the Newton's II law we can say
[tex]F_{net} = ma[/tex]
here if force is unbalanced then it is for sure that net force on the system is non zero
so here the object must have some acceleration here
so here we can say that object must have change in velocity due to unbalanced force present on it
now the correct option in this case must satisfy the change in velocity condition.
SO correct answers will be
Decelerate.
Stop moving.
Start moving.
Accelerate.
