A linear model was used to predict the weight of four different animals based on their length. The residuals (actual minus predicted…

Prediction accuracy depends on the size of the error, not its direction. A residual of $-3$ and a residual of $+3$ are equally far from the line. Compare the absolute values: $|+2| = 2$, $|-1| = 1$, $|+5| = 5$, $|-3| = 3$. The largest is 5, so the animal with a residual of $+5$ pounds was modeled least accurately, choice D. Choice A ($-1$) is the most accurate, with the smallest error. Choice B ($-3$) is the tempting choice if you treat the most negative value as the worst. Choice C is false, since the errors differ.