A force of 100 N will exert the greatest pressure on an area of

It will apply the greatest pressure of an area of 1.

Explanation:

To find pressure use the formula P = F/A

P = 100/1

P = 100

10 N / cm^2

Explanation:

The Formiula is P = F / A

P = presure

F = Force in Newtons

A = area.

The answer is the smaller the area the larger the pressure.

The smallest area you have given us is 10 cm^2

The Pressure = 100N / 10 cm^2

Pressure = 10 N/cm^2  

Note: the units are not exactly standard units, but I've given the answer the way the question offers the units.

c) up is the direction the magnetic force is acting on the charge.