12. The units of \( \frac{1}{4\pi\varepsilon_0} \) are:
(A)\( N^2 \cdot C^2 \)
(B)\( N \cdot m/C \)
(C)\( N^2 \cdot m^2/C^2 \)
(D)\( N \cdot m^2/C^2 \)

(E)\( m^2/C^2 \)

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