Comparison of Electrostatic and Gravitational Force

Question

$\begin{array}{1 1} \text{(a) Both gravitational and electrostatic force are always attractive in nature} \\\text{(b) Both are conservative forces effective even in free space } \\ \text{(c) Gravitational force are extremely large compared to electrostatic force} \\ \text{(d) Electrostatic constant of proportionality is a universal constant} \end{array}$