Charge Q Is Distributed Uniformly Throughout an Insulating Sphere of Radius

Multiple Choice

Charge Q is distributed uniformly throughout an insulating sphere of radius R. The magnitude of the electric field at a point R/2 from the center is:

A) Q/4 $\pi$$\varepsilon$ ₀R²
B) Q/ $\pi$$\varepsilon$ ₀R²
C) 3Q/4 $\pi$$\varepsilon$ ₀R²
D) Q/8 $\pi$$\varepsilon$ ₀R²
E) none of these