An Insurance Underwriter Wonders Whether Sports Cars "Cause" People to Drive

An insurance underwriter wonders whether sports cars "cause" people to drive too fast or whether those with a propensity for speeding are drawn to sports cars. She secures some research funds and recruits 100 car buyers to her study. She randomly assigns 25 drivers to each of four groups: 1) sports car white, 2) sports car red, 3) sedan white, or 4) sedan red. The primary research questions are: 1) Do sports cars make people drive faster? and 2) Does color make a difference? This study has:

A) four treatments.
B) two treatments.
C) four treatments and a placebo.
D) two treatments and a placebo.