shortest distance =∣p×q∣∣(a−b)∣⋅(p×q)
where
$\begin{aligned}
& \overline{\mathrm{a}}=-\hat{\mathrm{i}}+0 \hat{\mathrm{j}}+0 \hat{\mathrm{k}} \
& \overline{\mathrm{b}}=\mathrm{p} \hat{\mathrm{i}}+2 \hat{\mathrm{j}}+\hat{\mathrm{k}} \
& \overline{\mathrm{p}}=3 \hat{\mathrm{i}}+4 \hat{\mathrm{j}}+5 \hat{\mathrm{k}}-\overline{\mathrm{b}}=(-1-\mathrm{p}) \hat{\mathrm{i}}-2 \hat{\mathrm{j}}-\hat{\mathrm{k}} \
& \overline{\mathrm{q}}=2 \hat{\mathrm{i}}+3 \hat{\mathrm{j}}+4 \hat{\mathrm{k}} \
& \frac{1}{16}=\frac{|-1-\mathrm{p}+4-1|}{\sqrt{6}} \
& |-\mathrm{p}+2|=1 \
& \mathrm{p}=3 \
& \frac{\mathrm{x}^2}{1^2}+\frac{\mathrm{y}^2}{3^3}=1 \
& \mathrm{L} \cdot \mathrm{R}=\frac{2 \mathrm{a}^2}{\mathrm{~b}}=\frac{2 \times 1}{3}=\frac{2}{3}
\end{aligned}$
option (3)