Answer:
Halve the plate separation and double the plate area
Explanation:
Since capacitance is given by [tex]C=\frac{\epsilon_{o} A}{d}[/tex]
Where A is the plate area and d is the plate separation, decreasing the separation by 0.5 and doubling the area will make the capacitance increase 4 times if [tex]\epsilon_{o}[/tex] is constant. Therefore, Halve the plate separation and double the plate area
