b
Observer is in motion and source is at rest.

\(\Rightarrow n^{\prime}=n \frac{v-v_{O}}{v+v S}\)

\(\Rightarrow \frac{94}{100} n=n \frac{330-v_{O}}{330}\)

\(\Rightarrow 330-v_{O}=\frac{330 \times 94}{100}\)

\(\Rightarrow v_{O}=330-\frac{94 \times 33}{10}=\frac{33 \times 6}{10} m / s\)

\(s=\frac{v^{2}-u^{2}}{2 a}=\frac{9 \times 33 \times 33}{100}=\frac{9 \times 1089}{100} \approx 98 m\)