Which of the following is acceptable on GMAT and why?
Whether: eg. To this day, researchers and theorists debate whether bubonic plague caused The Black Death, a pandemic that swept the world in the middle of the fourteenth century.
Whether or not: To this day, researchers and theorists debate whether or not bubonic plague caused The Black Death, a pandemic that swept the world in the middle of the fourteenth century.
Whether: eg. To this day, researchers and theorists debate whether bubonic plague caused The Black Death, a pandemic that swept the world in the middle of the fourteenth century.
Whether or not: To this day, researchers and theorists debate whether or not bubonic plague caused The Black Death, a pandemic that swept the world in the middle of the fourteenth century.
