In an experiment designed to measure the distance a golf ball is hit by clubs made of different material, a standardized variable would be:
A The distance the golf ball traveled B The type of material the club is made of C The material the golf ball was made of D The wind direction when the experiment took place
E Both the wind direction when the experiment took place and the material the golf ball was made of are correct
I think it is b but for some reason I am thinking it may be wrong.