d
\(\mathrm{X}_{\mathrm{L}}=\omega \mathrm{L}=100 \times 1=100 \Omega\)

\(\mathrm{X}_{\mathrm{C}}=\frac{1}{\omega \mathrm{C}}=\frac{1}{100 \times 20 \times 10^{-6}}=500 \Omega\)

\(\mathrm{Z}=\sqrt{\left(\mathrm{X}_{\mathrm{L}}-\mathrm{X}_{\mathrm{C}}\right)^2+\mathrm{R}^2}\)

\(\sqrt{(100-500)^2+300^2}\)

\(\mathrm{Z}=500 \Omega\)

\(\mathrm{i}_{\text {ms }}=\frac{\mathrm{V}_{\text {ms }}}{\mathrm{Z}}=\frac{50}{500}=0.1 \mathrm{~A}\)

\(\text { rms voltage across capacitor }\)

\(\mathrm{V}_{\text {ms }}=\mathrm{X}_{\mathrm{C}} \mathrm{i}_{\mathrm{mms}}\)

\(=500 \times 0.1=50 \mathrm{~V}\)