You don't need an SAT score to graduate from high school. SATs are for college admissions. However, you do need a total of 24 credits to graduate from a public high school
The formula for Sums of squares of the residuals (SSR) is attached below.
Therefore, option B is correct:
B. I would calculate the difference between the observed outcome (Y) and the predicted value of Y (Y_hat), square each one of these differences, and add them up.