According to newton’s second law of motion, an object will accelerate if you apply what kind of force?
a. inertial force
b. frictional force
c. balanced force
d. unbalanced force

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.