Two point charges $\;q_{1}$ and $\;q_{2}$ are placed at a certain distance d from each other . The interacting force between them is F . Now both charges kept in oil of relative permittivity 5 . What is the new value of force between them

Question

$(a)\;\large\frac{F}{2}\qquad(b)\;\large\frac{F}{4}\qquad(c)\;\large\frac{F}{5}\qquad(d)\;\large\frac{F}{25}$