I want to know whether drivers who drive with their headlights on in the daytime are less likely to accidents. I require 100 drivers from a large company to drive with their lights on during the day and require another group of 100 drivers from the same company to keep their lights off. I then keep accident statistics for several years to see if there are any differences. Having the lights on or off in the daytime is a. a confounding variable. b. the independent variable. c. a random variable. d. the dependent variable