A golfer wants a new set of clubs to improve her game.In an experiment,she goes to the driving range and compares the distance she hits a bucket of golf balls with drivers of different materials in the head before making her purchase decision.In this simple experiment,the independent variable is the
A) swing speed of the golf club prior to striking the golf ball. B) wind direction when the experiment took place. C) type of material used to make the club head. D) distance the golf ball traveled. E) type of material used to make the golf ball.