What is the net electric flux within a Gaussian surface is directly related to what physical quantity/quantities?

a) the area chosen
b) the amount of charge enclosed by the area
c) both the amount of charge enclosed by the area and the area chosen

The whole point is that the total flux through the surface is proportional to the enclosed charge. If the surface surrounding a point charge is a sphere, the E field drops with the radius squared so that the integral of E d area is constant as you get further away.

The net electric flux within a Gaussian surface is directly related to both the amount of charge enclosed by the area and the area chosen. The electric flux represents the amount of electric field passing through a given surface. It is calculated by taking the dot product of the electric field vector and the perpendicular area vector of the surface. The amount of electric flux is influenced by the charge enclosed within the surface because the electric field lines originating from the charge contribute to the total flux passing through the surface. Additionally, the choice of the surface area affects the total flux, as a larger surface area allows for more electric field lines to pass through, resulting in a greater flux value. Therefore, option c) both the amount of charge enclosed by the area and the area chosen is the correct answer.