According to Coulomb's Law, the amount of electric force depends on which two things?

a
the size of the charge on each of the two particles and the distance between them
b
the mass of each of the particles and the distance between them
c
the size of the charge on each of the two particles and the gravitational force between them
d
the mass of each of the particles and the gravitational force between them

a) the size of the charge on each of the two particles and the distance between them.