Drivers report that their symptoms of road rage can be reduced if the driver they are angry with

Makes a gesture of apology.

Explanation:

When someone causes you to drive badly on the road and they show no remorse for their actions , it is most likely infuriating because you almost lost your life and it seems the person responsible for that doesn't even care.

However if a person shows a gesture of apology it is likely to indicate that they see their mistake and they are sorry for that, as a human being it is easy to settle down your anger when someone humble themselves and show an apology.

The best answer to the question above would be letter c. Mikhail Gorbachev's - during the Cold War - policies of perestroika and glasnost meant restructuring and openness. Both words respectively literally translate from Russian to English as aforementioned.