A car’s speedometer display is proportional to the tyre rotation rate. If the tyre diameter changes as the tyre wears, the speed reading on the speedometer becomes inaccurate. A car is fitted with new tyres that each have a diameter of $600\,\text{mm}$. The speedometer has been correctly set for this diameter. As the tyres wear, $6\,\text{mm}$ of material is removed from the outer surface, as shown. Determine the error in the speed indicated by the speedometer after this wear occurs.
- AThe speed shown is too high by $1\%$.
- BThe speed shown is too high by $2\%$.
- CThe speed shown is too low by $1\%$.
- DThe speed shown is too low by $2\%$.