Well visual and perceptual are both the way you see things and tactile is touch so it has to be Olfactory
This is true. let me know if im wrong.
Answer:

Explanation:
First, we are going to calculate the electrical potential in the point middle between the two charges
Remember that the electrical potential can be calculated as:

Where 
and it is satisfy the superposition principle, thus


The electrical potential at 10 cm from charge 1 is:


Since the work - energy theorem, we have:

where q is the electron's charge and m is the electron's mass
Therefore:


You have to decrease the length of the pendulum by 4 times in order to make the clock go 2 times faster