For question 22, I was between choices A & C and I'm having trouble reasoning why the answer is C.

A) These places also have laws about other aspects of bicycle safety.

This seems like it can be the correct answer choice because if these places have other bicycle safety laws, it makes sense that riding on the left vs not riding on the left doesn't impact collisions much, since they have other measures to combat collisions, or whatever. However, since it was outlawed, and assuming that riding on the left leads to more collisions, the collision rate only decreased slightly, since there are other laws protecting bicyclists' safety.

C) Police officers in these places do not enforce regulations that apply to bicyclists.

I understand this is the right answer because while some may have stopped riding on the left since it was outlawed, many did not because the police weren't enforcing this law, therefore, leading to only a little decrease in collisions (the people who decided to follow the law). However, the assumption in this seems (that bicyclists continue riding on the left despite being against the law) to be greater than the assumption made for A (that other safety laws can combat the rate of collisions in general).

Can someone explain?

Thanks