An insurance company wants to know if the average speed at which men drive cars is higher than that of women drivers. Which of the following is NOT a possible confounding variable and choice to address that variable? O Type of driver, so commercial vehicles should be excluded from measurement. O Amount of traffic, so the speeds should be measured at the same time of day. O What roads are driven, so the speeds should be measured on the same highway. O Make of car, so the researchers should pick one make and only measure that. O Road conditions, so the speeds should be measured at the same sites