Which one of the following is volatile?

The answer to this is A. RAM is considered to have a volatile memory because if in case the computer is turned off while it is being used, you can already expect that the memory that you have stored in it will just disappear. This explains why you need to save your documents, projects, and other activities that you are doing while you can.

If there is brownout or your laptop or computer loses power, you will lose all of the progress that you have made. Your two options are to wish that the recovery feature of the app that you are using will work and the second option is to just start all over again.