One aspect of historical research and inquiry is to cluster events and concepts into meaningful groupings, sometimes by time period. use the table below to organize the events above by their correct era. as an example, the first event has been completed.

Which of the following  bestillustrates a negative reinforcer?               a.  copland gives up candy to stave off chronic acid indigestion.    b.  nancy learns that she prefers chocolate over vanilla.    c.  carmine changes his major to english lit after failing a math exam.    d.  on a hot day, lindberg always drinks lemonade.