This question is poorly stated, but I assume you mean what conditions are needed. It would have to be cold outside, correct?
C. It is answered by observation and evidence.
Good scientific explanations are defined, measurable and controllable. They can be answered by an experiment.
I attached the full question.
We know that for a parallel-plate capacitor the surface charge density is given by the following formula:

Where V is the voltage between the plates and d is separation.
Voltage is by definition:

Voltage is analog to the mechanical work done by the force.
Above formula is correct only If the field is constant, and we can assume that it is since no function has been given.
The charge density would then be:

Please note that elecric permittivity of air is very close to elecric permittivity of vacum, it is common to use them <span>interchangeably</span>.
P = U × I
I = P / U = 1600W / 120V = 13.4A
P = 240V × 13.4A = 3216W
If your hair blower isnt rated for 220- 230V(this is the voltage in EU) you are most likely going to burn it.