If you got this question from a book or homework sheet, then you should take it back and comp[lain. It's a defective question.
It's fishing for the answer "unbalanced force", but that's a misleading and misuse of the term. There's no such thing as a "balanced force" or an "unbalanced force".
A GROUP of two or more forces can be balanced ... if the forces all cancel each other out and add up to zero ... or unbalanced ... if they don't. But it's never correct to apply that description to a single force.
According to Newton's second law of motion, an object will accelerate if the forces on it are unbalanced.
