10. A nonconducting sphere of radius 10 cm has charge uniformly distributed throughout its volume. The electric field is directedradially outward and its strength at 5 cm from the center is 2000 N/C. What is the volume charge density of the sphere?(∈0 =8.85×10−12C2 /N·m 2 ）.
(A) 1.06 µC/m3
(B) 2.12 µC/m^{3 
(C) 3.16 µC/m3 
(D) 4.06 µC/m3 
(E) 5.18 µC/m3}