Do you agree with the following statement? "Checking whether the sum of residuals is zero is sufficient to conclude that a linear regression model is appropriate."

A. No, the sum of residuals will never add to zero. It is either $+1$ or $-1$.
B. Yes. In fact, examining only the scatterplot of $Y\,$ vs. $X$ is sufficient to conclude that a linear regression model is appropriate.
C. Yes, the sum of residuals equating to zero confirms appropriateness of a linear regression model.
D. No, the sum of residuals will always add to zero. One should also check the residual plot. If there is a pattern in the residual plot, it indicates that a linear regression model is NOT appropriate.