c
\(\overrightarrow{\mathrm{E}}=\overrightarrow{\mathrm{E}}_{1}+\overrightarrow{\mathrm{E}}_{2}\)

\(\mathrm{E}=\mathrm{E}_{1}+\mathrm{E}_{2}\)

\(E=\frac{\lambda}{2 \pi \epsilon_{0} R}+\frac{\lambda}{2 \pi \epsilon_{0} R}\)

\(\mathrm{E}=\frac{\lambda}{\pi \epsilon_{0} \mathrm{R}} \mathrm{N} / \mathrm{C}\)