ABC company wants to understand to what extent the supplier XYZ's process parameter x affects its process outcome quality y. In a simple linear regression analysis, the following sum of squares are produced: Σ(yi-y)²=480, Σ(yi -ŷ)² = = 120, Σ(ŷi-y)²= 360 The proportion of the variation in y that is not explained by the variation in x is: A. 20% B. 75% C. 25% D. 50% E. none of the above.