In a Laboratory, Smokers Are Asked to "Drive" Using a Computerized

Multiple Choice

In a laboratory, smokers are asked to "drive" using a computerized driving simulator equipped with a stick shift and a gas pedal. The object is to maximize the distance covered by driving as fast as possible on a winding road while avoiding rear-end collisions. Some of the participants smoke a real cigarette immediately before climbing into the driver's seat. Others smoke a fake cigarette without nicotine. You are interested in comparing how many collisions the two groups have. In this study, the independent variable is __________

A) the use of nicotine.
B) the use of a driving simulator.
C) the number of collisions.
D) the driving skills of each driver.