The choice of 60 centimetres is incorrect because it exceeds the acceptable distance for parallel parking. Parking this far from the curb can obstruct traffic and increase the risk of collision with moving vehicles. Drivers may choose this mistakenly due to unfamiliarity with specific local regulations. To avoid such mistakes, always check the local parking guidelines which specify 30 centimetres as the proper distance.

Selecting 120 centimetres is erroneous as it places the vehicle at a considerable distance from the curb, likely obstructing traffic flow and posing a hazard. Such a large gap can lead to accidents or disruptions in traffic patterns. This option may result from a misunderstanding of metric dimensions or a lack of knowledge of local rules. It's crucial for drivers to measure parking distances accurately and adhere to the recommended 30 centimetres.

90 centimetres is incorrect because it is too far from the curb according to BC’s parking regulations. Parking at this distance can cause the vehicle to intrude into the lane, creating a hazard for passing vehicles. Often, this choice comes from underestimating the specified parking regulations or a general habit of leaving a larger margin. To avoid errors, drivers should practice estimating and judging parking distances, aiming for the recommended 30-centimetre gap.