Answer:
e.)At twice the distance, the strength of the field is E/4.
Step-by-step explanation:
The strength of the electric field at a certain distance from a point charge is given by:

where
k is the Coulomb's constant
Q is the charge
r is the distance from the point charge
In this problem, the distance from the point charge is doubled:
r' = 2r
So the new electric field strength is

so, at twice the distance the strength of the field is E/4.