According to the rational root theorem -7/8 is a potential rational root of which function.
A.f(x)=24x^7+3x^6+4x^3-x-28
B.f(x)=28x^7+3x^6+4x^3-x-24
C.f(x)=30x^7+3x^6+4x^3-x-56
D.f(x)=56x^7+3x^6+4x^3-x-30