Which sentence in the selection “Bike Sharing” is an example of counter argument?

Which sentence in the selection “Bike Sharing” is an example of counter argument?

In big cities, where traffic can be frustrating and problematic, public transportation doesn’t always fill the gaps.

With a bike-sharing system, storage isn’t a problem because you don’t own the bike.

One problem with using a bike is safety.

They also found that bike sharing may move people from one place to another more quickly and directly than buses and trains.

One problem with using a bike is safety.