Let K Denote 1/4 $\pi$ $\varepsilon$ ₀

Let k denote 1/4 $\pi$$\varepsilon$ ₀. The magnitude of the electric field at a distance r from an isolated point charge q is:

A) kq/r
B) kr/q
C) kq/r³
D) kq/r²
E) kq²/r²