Let's think about how the statement in question is presented. It would be one result of the city actually caring about biker safety.
city cares ---> driver education
But the city did not do this, implying that they do not care.
no driver education ---> city doesn't care
From this, the author concludes that the city is more concerned with the appearance of bicycle safety. In this sense, the statement in question is partial support for the conclusion. You understand why B is correct.
Here is my problem with answer choice E. The statement about driver education is an illustration of a city that truly cares about its cyclists. The city does not match this illustration. If E were correct, we would see an example of the city prioritizing its image, like holding a press conference to roll out the helmet rule. I like to think of "illustration" and "example" as nearly synonymous on the LSAT.