Since the charge has a direct proportionality, the increase will be a factor of three. But, since you triple the distance, which has an inversely squared proportion, it will be 3/9 F or
1/3 F.
*This is all based on the fact that this is true:
Answer:

Explanation:
From frequency of oscillation

Initially with the suspended string, the above equation is correct for the relation, hence

where k is force constant and m is the mass
When the spring is cut into half, by physics, the force constant will be doubled as they are inversely proportional

Employing f2/ f1, we have

I guess the correct answer is the first one.