Biologists Studying the Relationship Between the Number of Round Goby

Biologists studying the relationship between the number of Round Goby (an invasive prey fish) and the number of salmon eggs in streams believe that the deterministic component of the
Relationship is a straight line. A scatterplot shows that even though the general trend is linear, the
Points do not fall exactly on a straight line. Which of the following factors might account for the
Random component of this regression model?

A) Variation in the size of the Goby might cause variation in the amount of salmon eggs consumed.
B) Variability might appear in the instrument used to count salmon eggs.
C) Different size salmon might affect the number of eggs laid.
D) All of these are possible factors that could account for the random component of the regression model.