As per Newton's II law we know that
[tex]F_{net} = ma[/tex]
here we know that
[tex]F_{net} = F_{ap} - F_f[/tex]
so here we will have
[tex]a = \frac{F_{ap} - F_f}{m}[/tex]
so here if we need to increase the acceleration we need to increase the applied force while on increasing the mass or on increasing the friction force the acceleration will decrease.
So here correct answer will be
A) force on the object.
