Answer:
A.One q would be doubled and r would remain the same.
Step-by-step explanation:
As we know by Coulomb's law of electrostatic force is given as

As we know that the distance between the two charges is given as r
and the two charges are given as q1 and q2
so from above equation we can say that if we double either of the charge then the electrostatic force will double
so we have

so we have

So correct answer will be
A.One q would be doubled and r would remain the same.