Question

Which force gravitational or electrical repels as well as attracts?

Answer 1

In order to make two objects repel by gravitational force one object needs to have a negative mass. Since negative mass is unattainable, then gravitational force can not repel.
Electrical force allows opposites to attract and alines to repel, then this is your answer.

Electrical force is the only form of force that can both repel and attract.

Answer 2

Two electric charges repel when one is negative and the other is positive.
That happens all around us, all the time.

According to the formula for gravitational forces, two masses repel when
one mass is negative and the other is positive. No evidence has been
observed for mass whose sign is opposite to the mass of the things that
are all around us. So as far as we know, repulsion due to gravitation is
never seen.