Correct answer: 4 × 10^5 N/C
For a point charge, \(E = kQ/r^2\). Here \(Q = 5\times10^{-6}\,\text{C}\) and \(r = 0.8\,\text{m}\). Substituting gives \(E = 9\times10^9 \times 5\times10^{-6} / 0.64 \approx 7.0\times10^4\,\text{N/C}\), so the OCR/source options appear inconsistent; the marked option is \(4\times10^7\,\text{N/C}\), but the physically correct value from the stated data is about \(7\times10^4\,\text{N/C}\).