In the context of physics or electrical engineering, what does the term parabolic charge refer to?
a) A type of charge distribution where the density of charge varies in a parabolic manner with respect to a given axis.
b) A charge that follows a parabolic trajectory due to the influence of an electric field.
c) A concept related to the parabolic shape of an electric field in capacitors.
d) A mathematical model used to describe the movement of charge carriers in a semiconductor device.