Step 1: Understanding the Concept:
Gauss's law states that the net electric flux through a closed surface is \(\Phi=\dfrac{q_{enclosed}}{\varepsilon_0}\).
Step 2: Apply:
The point charge stays inside when the sphere is enlarged, so \(q_{enclosed}\) does not change. The flux remains \(\dfrac{q}{\varepsilon_0}\).
Step 3: Why the other options are wrong.
The field falls as \(1/r^2\), but the area grows as \(r^2\), so their product is constant. Flux does not rise, fall, or become zero.
Final Answer:
The flux remains unchanged.
\[ \boxed{\text{(B) }\text{remains unchanged}} \]