Answer:
a.

b.Repulsive
Step-by-step explanation:
We are given that



r=1.66m
We know that
Electrostatic force =

r=Distance between

k=Constant=

Using the formula
a.The magnitude of the electrostatic force=

The magnitude of the electrostatic force=

b.Both charge are positive .We know that when like charges repel each other and unlike charges attract to each other.
Therefore, the force between given charges is repulsive.